I wouldn't call eB "Evilbay." Yes there's a mixture of good and bad sellers so customers should learn to be beware and weed out the latter. That said, one thing that makes eB "Evil" is their current sales surcharge policy (under eB Managed Payments), which takes off roughly 13% of each successful eB sale. And with that, sellers have to take that into account and have no choice but to bump up prices just to offset those charges. This has become increasingly common with Surefire components over the past two years or so (especially since the later half of 2020)
I too sell at eB, because everything seems to be arranged (despite the heavy fees). Not that I'm bashing CPFMP but it takes great courage and much more time to manage and monitor sales threads here. I even paid for CPF account upgrade but that didn't quite pay off (ie. help me with MP sales and such), even though I'll continue to try. I don't however see a problem listing on multiple platforms, as long as the person concerned observes all rules. But I must agree, at CPFMP you get better quality people selling stuff, ie. those with better reputations than some nobody.
As for FB and other web platforms, well, YMMV. I've seen worse when it comes to Surefire sales. Most of such bad examples involve not posting enough listing photos to depict the actual condition of the item concerned, even after multiple PM inquiries.