Maybe Facebook, etc., have this problem too, but I gave up on selling things locally. These days I just try to pass things on to friends and family.
Then there were the obvious scams (I don't understand how they work, but they were clearly not legit buyers). Where someone's first message is a demand for your Venmo or Zelle account name, and when you respond with anything but what they asked for they just disappear.
And finally there's the perverts who see a woman posting online and use it as an avenue to sexually harass her. Aggressive demands for address and phone number right off the bat, unsolicited nude photos, it's extremely gross.
So, yeah, I would say the experience of posting on Facebook Marketplace is as bad or worse than anything else. Especially if you're a woman.
(personally, I've found myself doing this and then having to stop because the seller isn't some big mega corp, but just some random other working class friend)
I've said "nope" and walked away from cash sales that try that nonsense. and the whole experience soured me on Craigslist for quite a while.
also, around here there are a ton of small businesses that basically flood the listings with whatever they can. it's not even a person selling the stuff, it's a storefront.
Seller: $5500 firm, no trades
10 people/day: Will you take a '83 suzuki 3 wheeler (stolen, doesn't run) and $97.24????