yeah i totally agree that it often is a nice gesture of support.
personally though, if i really think about it, the supportive gestures that have genuinely meant something to me, that i remembered, have not been likes but articulated engagement and acknowledgement.
and yeah, there's no fundamental difference between liking someone's post and saying "good point". but i do think that if we had to do the latter, we might more frequently add another thought in--and would be less inclined to interpret the absence of such outright validation as rejection (though maybe that's just me and Corpsey lol), since people would probably say "good point" more selectively, not so much as a common courtesy.
so i don't know exactly what would come of a boycott, but i think after a while it might actually lead a better atmosphere: more fluent and populated conversations, and fewer (or less defined) assumptions of what other people think of what you're saying. always having you head in the right place. i could be wildly projecting tho