I don't think anyone is doing that. It's just the case that many (most?) people are happier and more fulfilled in a committed, long term relationship. It doesn't mean that there aren't people for whom that's not the case, and it doesn't mean that those people are somehow defective.

But this entire post is about how some people get sad, angry, and/or hateful when they want to be in a relationship but continually fail at it. It seems off-topic and missing the point to bring up a "well, actually" about how some people don't want or need that.