I get what you mean, but it also meaningful in a group dialogue to show who (and how many) agree(s) with your posts.
If someone made the best post ever (unlikely to be me!) then there is no real feedback that shows that is the case… the people most likely to engage with the post with a response are people that disagree with it. There’s often not anything to add when you agree with someone that’s well said… and I think people would rather a ‘like’ than additional posts saying ‘good post’.
Maybe... influencers like 'likes' because it helps them decide on future content. I guess some people appreciate likes to tell them they're thoughts align with others.
As with everything else, the 'numbers' on a forum are pointless. Unless you're able to take the number of likes, ratio it against the number of views, and decide that's an overall 'win' ?
I'd much rather assume that anyone disagreeing will state as such - ideally with a reason why - and silence is 'agreement' or 'ambivalence'. Then again, I just post what I think, when the desire takes me, and couldn't care less about reactions, unless it's the laughter emoji against a serious comment, which is where it comes back to emotion and why I agree with the emojis being removed. As stated previously, if they were just 'agree' or 'disagree', with emotion taken out, there's less ambiguity and likelihood of misunderstanding.
XKCD 386: Duty Calls, is to this day one of the most comprehensive answers.