I have never said that subreddits should go away. Ever. Each post that again argues one versus the other is tossing up a distraction.
They are not for finding people that agree with you
Correlation isn't about agreement: An upvote does not mean "I agree with this". It means "I found this interesting/useful/enjoyable/educational", whereas a downvote should mean "I find this uninteresting/not useful/unenjoyable/not educational".
In no universe does that preclude learning new things. Quite the contrary, in fact.