There strategy did not make any sense: only a few pre-approved broad-and-shallow forums about everything instead of trying to attract niche communities from Reddit or even FB Groups.

Why doesn't that make sense?

Because there's no real discussion in such broad communities. Only jokes, generic replies, and silly fights. They're equivalent to comment sections on news sites.

And it doesn't make sense to you that someone might make money from a platform without discussion?

They introduced user-created communities a few months ago. They had problems with squatting and splintering, which might have played a role in their annoucement.