I don't think that's the problem. Sure, we might had more people discussing if there was an app as much friendly as Twitter, but it wouldn't rise the overall quality. I've caught myself shitposting on my mobile. It's self-encouraging, because you're typing with your thumbs and you can't be typing for a long time.

Facebook isn't known to having freedom of speech. Plus, lack of anonymity makes it even worse to opening up yourself freely. (e.g., you wouldn't publish your TXID in a FB group in case you had a technical problem)

Time flies, doesn't it? At that time, I wasn't aware of how it works at all.

It's one of the worst platforms, though. You're forced to summarize everything within a few hundred characters, and there are shitcoin-shilling bots everywhere, even in advertisements.