1.The job opportunities for the 2nd language speakers are a very real thing for people with other native languages than English or a few more huge ones.
Also, the "we've never hired 2nd language speakers for the job, only natives" experience calls for a follow up question: "and what kinds of candidates were you refusing,what were their language skills?". Perhaps only badly speaking 2nd language speakers were applying, or they were simply worse in other aspects than the successful candidates who also happened to be natives of the demanded language.
3.The quality of translations is also a thing. There are some excellent translations and dubbing, and then there are crappy ones. I had to turn the tv off yesterday, when I saw a few minutes of Sherlock dubbed in Czech. Horrible. And I hated a translation of a French crime novel, where the translator basically dared to correct the author and made the characters use different (too polite) kind of language, and those are just two examples out of many.
Also, lots of stuff simply doesn't get translated.
And if number 3 is snobbery, I have no problem with it, having heard my fair share of sports related snobbery (basically all those comments in a certain tone concerning any non-sport hobbies being a waste of time, and so on.)
Something related that almost never gets mentioned: the prices. This is one of my reasons for learning German, the books are cheaper. And dvds (even the same ones with the same sound and subtitle options. And we are not talking about a few cents of difference, we are talking about the normal western price being tripled for people in a much poorer central european country, who also don't get the same quality of the legal streaming services for the same price). When it comes to books, there are different "traditions" of the market like whether the preference of paperback vs hard cover and so on, and also the prices in general. I could talk about this for a long time with practical examples and explanations (for example, the Czech translation is often twice as big as the original book due to stupidly thick paper, hard cover, and large font, so that the publisher can justify the high price. and these books are also not practical to carry around and read in public transport). So, I can either buy a book damaged by the translation, or I can pay the same price for two or three books in original.
Or the same medical textbook costs much less in original than in translation and you get the up to date edition instead of the ten years old one.
And don't forget the news. One doesn't need to be a conspirationist to notice the differences in the same story, depending on who is writing about it and where is the newspaper published. Foreign languages give us the freedom to look at the bigger picture.
2.well, almost any activity people do is good against brain deterioration. Language learning is a nice option but I personally doubt it would work that great on its own, I totally agree other measures should be addressed first. And people don't care much anymore about their health, until it is too late anyways.
4.Making friends, that is a popular reason but the most tricky one. Making native friends even in the supposedly ideal situations doesn't often go so smoothly. Learning a language just to communicate with people directly is probably the fastest way to disappointment and/or burn out.
So, if there was any chance to flood the internet with less kitsch and more meaningful lists of reasons to learn foreign languages, I would spread something like this:
1.Freedom to move abroad, should you ever want or need or have to
2.Job opportunities, if you learn a set of skills fitting the chosen language and career path too
3.Cheaper and better media of any kind, as you'll be choosing from a much wider selection
4.Understanding others much better, thanks to knowing a bit more about their culture, thinking, and also thanks to easy eavesdropping
5.Bragging rights. It is cool to know a language. People may discourage you at first but your success will change their attitude and behaviour