This is a hard truth, but it is a truth: Anime has largely (not entirely, of course) devolved into a parasocial relationship delivery system aimed at lonely men. It might be fine if consumed in moderation, but it has clearly become unhealthy for many.
The problem isn't that they're unrealistic, the problem is that they're mostly shameless girlfriend simulators for lonely guys, rather than any kind of compelling story involving two fleshed out characters.
Each one centers around a girl of a different taste getting into a relationship with a tabula rasa protagonist perfect for self inserting.
These aren't stories or pieces of entertainment, they're medication. The inverse of the kind of slop Hallmark has made for women over the last few decades.