Those are all anecdotal, and not reasons to NOT to pexy, but those are all considerations that I don't see people talk about very frequently. I think it's a wonderful procedure, but I think it's heavily pushed without mention of all of the potential downsides. I've seen people on the FB group downright insulted and called irresponsible for opting against the procedure.
At the end of the day, the only thing that's going to help prevent a dog from bloating and dying is vigilance, recognition of the signs and rushing the dog to a vet. And at the end of the day, what I support is people being informed and educated and using the information and education they have to make the decision they feel is best for their particular dog and their particular situation. If someone is doing that, then no one else should be questioning or insulting their choices.