The only reason people make lists like that is because they can't fathom the understanding of the importance of foreign languages and they are the people who attempt to learn the language of their choice and sadly they give up after a week because they make pathetic little excuses like "it's too hard, I don't like their grammar, I can't say ____, their spelling is too long, I don't like it anymore" - when really they go around learning the language with a negative attitude and the wrong ethos. It's obvious to know that you need to understand grammar but before you can do that in the learning of a foreign language you need to build a vocabulary and know how to say basic phrases (which are classed as 'survival phrases') to be then be able to understand the concept of what a noun, verb, article (of which some languages don't have), definition, determiners, clauses, tense, paraphrasing etc mean.
Furthermore, you need to have the right attitude toward appraising that of a foreign language otherwise you'll never achieve what you think you can if you have the wrong attitude to it.
Looking at this list, I personally call it a pathetic, weak and stupid list because of the following reasons to some examples:
German - "It just sounds like someone is always yelling at you. If Hitler was to have a rally I would join because he sounds like he would kill my entire family." - What a pathetic excuse, that's why people underestimate German because they always relate it back to the historical time of Nazi Germany and people need to forget that and remind themselves that we are now in the C21. Plus, German is not only spoken in Germany but also in Austria, Switzerland, Luxembourg, Liechtenstein and Belgium - alongside others.
Danish - "Danish is by far the worst language in de world. It is a very poor attempt at immitating Swedish ... Besides, no one in the world speaks Danish except for the Danes." - Okay, well first off, Danish is closer connected to that of Norwegian - mostly Norwegian Nynorsk, but to an extent many linguists have made connections from Danish that are closer to Norwegian, using Bokmรฅl (Standard Norwegian) for example, if I were to say I: Jeg, in Danish it would be the same. Plus there is a mutual understanding across the three Scandinavian languages themselves, for example: (it is cold) N: det er kaldt,
det er koldt, S: det รคr kallt.
Chinese - "Ha ha, except there are thousands of Chinese dialects and at least 2 major kinds of "Chinese" which are Mandarin and Cantonese" - So this person doesn't accept that a Chinese language other than Cantonese or Mandarin is a language, even though a language (or dialect if you prefer) such as Chinese Wu has 77 million native speakers? ...
French - "Why do we have to learn french its so stupid." - Why are you stupid? I forget when to laugh when speaking French because I don't find it amusing at all ... in fact some 30,000 words in English are historically traced back to French.
Korean - "I think Korean sounds annoying, it seems harsh and masculine ... Its so hard to listen to K-pop can hardly make out each word" - Stop with your little pedantic comments and get back to studying? Obviously you can't be bothered to take the time to google the lyrics of a song ...
Shakespeare style English - "I mean what's with all the ths thow marrow hard and stupid only king use it any way!" - first off, if this person is a high school student, then I would have to give him/her an F. Secondly, it's not "Shakespeare style English" - it's called Shakespearean English, plus "only king use it any way" - that my friends shows bad grammar ... I think this person meant to say "only the king used it anyway".
Latin - "Its a dead language. Why would you waste your time on learning it!" - Because if it wasn't for Latin then most of the languages of Europe would not exist.
Russian - "using such an ugly language" - shut up, it's disgusting and annoys me when people condemn a language to be "ugly" because you obviously aren't capable of understanding the widespread difference of languages in the world and the fact that a word out of someone's mouth both theoretically and philosophically can mean a thousand more words that the one you say. To call a language "ugly" means that you don't have the patience to accept a language for what it is, I find Russian - alongside all languages to have such a beautiful sound to it and the literature and poetry from Russia is named some of the best in the world.
Gaelic - "Who would want to speak an old scottish/Irish language." - Because it's important to understand the heritage of where you're from and what the words themselves meant back in the historical times of people who lived before you. In addition, they're the most historical languages of the UK and if someone has the chance to speak it with their family then that is probably a privileged chance.
Greek - This language is one of the most historical in the EU and today it has many words mostly of a medical nature that originated in the historical Ancient Greek language. Greek is also a language with the use of a specific alphabet and the language has changed many years ago from Ancient Greek to Modern Standard Greek. Also, some of the Greek letters are used in modern mathematics.
Swedish - "When swedes talk it sound like are gobbling out weird noises" - then you're inept of understanding the fact that someone from Sweden could think the exact same as a speaker of English language. How can you make presumptions of a language when you probably don't even know 5% of the words spoken in it?
Spanish - "Spanish is the most horrible sounding language ever" - I don't really know how to respond to someone so dramatically pigheaded and uneducated.
All-in-all, this entire list is a bunch of absolute garbage, never in a million years would I condone a language to be "ugly" because of certain things that are sown to the said language because of people's misconceptions over many years that have been made. As per usual I would say that people who are unable to understand the concept of being bilingual are obviously the generic types of people that are mentioned across many websites that are to do with foreign language exchange and learning. I really hate these "lists" because it's people making stupid regards to something that passionately - I find very important in the world because without communication, how can the world run effectively?
Plus, when referring to my English speaking native background, I don't like how they're is the regard from a lot of the population of the UK (even the US) that if you are to go to another country, that they "will speak English" - no - they shouldn't have to. If you're going to go to another country, then you should take the time to learn simple words and phrases as a mark of courtesy and politeness. Instead of standing shouting at someone " WHERE. IS. THE. BANK. PLEEEEEASE?!" - you could simply learn less than 8 words to make a simple short phrase.
If people outside of the English speaking world take their time of learning English - as they're are double the amount of people who speak it as a second language to ourselves who speak it as natives - then we should take the time to learn a few words, it's not difficult after all.
Danish! 
Swedish 
Robbie 
Dimitris?