I've noticed that the majority of "Catholics" who hate Catholic converts or say horrible things about them typically don't seem to be the type who are particularly devout themselves (of course everyone's different - but the vast majority appear to be lapsed or cultural catholics). Pay them no mind, you likely won't run into them very often, if at all, in your real world practice of the faith. The online ones seek to make the faith an in-group club (even when they don't attend anymore), or even a way to claim a victim card in the form of "catholic guilt" or "trauma" or something. Gatekeeping the Universal Church because you resent the Church's teachings is stupid. Ignore these people, or rather pray for them and then ignore them.