You can learn by watching anime, but you'll sound like a 14-year-old. Japanese has various levels of politeness that need to be mastered if you don't want people to think you're an idiot.
*source: speak Japanese, lived in Tokyo since late 00s. I often sound like an idiot in Japanese, so don't get your pants in a bunch.
100%ing Shadow the Hedgehog might help you learn a language considering how many times you would have to complete the first mission (326 for every possible path). Plus you'd know the word "damn" VERY WELL.
I mean, you probably could eventually to some extent... definitely not enough to have a conversation, but you might be able to vaguely understand someone saying something to you.
There's a method of language learning - comprehensible input - that is basically this.
Though you need to start by watching/listening things you can actually understand. So start with Peppa Pig level, where they use basic vocabulary, repeat often, and use many visual aids, then work up to content for adults.
Trouble is finding enough learner level content to watch (without going insane). You need many hundreds of hours of content that you understand 90-95% of.
But even if you start with content way too advanced you'd be surprised what many hundreds of hours of listening to a language can do. Not efficient or recommended, but if they're ACTIVELY listening to the sounds of the language they could pick up a lot of meaning over such large amounts of time.
My high school Spanish teacher said she learned English after immigrating to the US by watching English soap operas like Days of Our Lives and things like that. I'm sure the same could be done but not sure how exactly. It would probably take a lot of active listening.
My MiL moved here from India and watched soap operas not just to learn idiomatic English but to learn how to dress for cold weather.
Growing up in Colombo and Chennai, it never got cold enough to need socks; she was in Midland Ontario and the soaps taught her how to wear snow boots, winter jackets, scarves, wool hats.
I learned a ton of Japanese from anime. I also took two semesters in college, but anime was a huge portion. I signed on as a translation cleanup guy for a fansub group back in the day. We had a guy in Japan who could write broken English for the dialogue in anime episodes, and then I was the guy who was excellent with English but only had a basic grasp of Japanese (grade school level). Between us, we could get a script.
I learned more from cleaning up his scripts than I EVER did in two semesters of college.
Nowadays, I am not sure what the word for it is, but I can understand spoken Japanese at a high level but I cannot speak back very fluently. My spoken word is full of pauses as I try to think of the right word. But if you speak to me in Japanese, I understand very well.
So... is the meme accurate? I guess partially. It's not like I would ever call myself fluent. I can just watch anime without subtitles now.
If you watched every episode with simultaneous Japanese and English captions, you technically could. Just need to focus on memorizing things and writing things down, as well as deciphering grammar.
Yeah, you would learn some things, but you'd end up speaking like cringy middle schooler. Business and daily life conversations are significantly different from anime and manga ones.
I had a roommate who could decently understand japanese this way. We had him look away and translate for us a few times and he was spot on. I'm sure if he put effort into speaking it he could have learned to do that as well.