It’s like I said on the “did this forum convert any atheists?” thread.
This forum had an identity problem. It was trying to be all things to all people who posted here.
People came here looking for all different stuff. One poster might want Catholic fellowship, another one wants a place to talk about all their personal troubles in life, a third is looking for an actual “Catholic answer” to a question they have, somebody else wants to pick holes in the Catholic faith, other people were seeking spirited “debates” of various levels of quality, and still others wanted a place to air their grievances with the Church/ Pope/ Catholic teaching/ their parish etc. Add in a ton of trolls and people who just shouldn’t be on the Internet period, and it had a bad tendency to explode.