Because let's be real, if you posted "It's a lovely day." on an internet forum you might get a response like "No it's not, noob."
LLMs are heavily weighted to give supportive, and constructive responses.
I wonder what they might be like without these limitations? Without the limitation to make the response from another user they might be much less deceptive.
That they are popular shows that many people just want a nice moderated online community where people treat each other with respect.