Yeah stack exchange is proprietary, but community there extremely care about quality. on the other hand, it is common in Lemmy to post one liners, poorly reflected, unrelated, irrational good feel answers. And it is filled with extremist crazies & bad faith actors. Also keep in mind, when contributing to federation platform that you are also giving more voice to extremist crazies, but IG it can be overlooked if other platforms are censoring basic freedom of speech.
This post is kind of ramble-y and hard to follow, I don’t care either way about stack exchange or Lemmy, but it genuinely took me a while to figure out what you were trying to say here