It is completely possible to dive beautifully in any gear. I have seen photos of Diver0001 in the Red Sea, in a rental BCD, looking like the dolphin he's watching. I have dived with Charlie99, who dives like a fish, and doesn't use a backplate or a long hose.
I don't try to tell anyone that the system in which I dive is the only way to dive. I love it, myself; I find the advantages of standardized equipment, standardized procedures, and a strong emphasis on high quality skills to make for a wonderful dive community. In addition, for reasons I don't completely understand, our community seems to epitomize mentoring and generosity to new and upcoming divers, which is how I got shanghaied in the first place.
I think, in general, when someone finds something that really works well for them, they get very animated and fervent in advocating that thing, whether it's Force Fins, backplates, or DIR diving. I can forgive people for being passionate -- it beats not having opinions, or not having any experience. I think people on SB are less intolerant than the OP might suggest, though. We love the gear we have, and the training we've had, and the diving we do. But rarely, if ever, do I see someone say, "If you don't do such and such, or own such and such, you shouldn't be diving and you're a danger to self and others." I see that said about dangerous ambitions (there are two threads running currently about that) but not about gear, or diving styles.