I believe they think it's a privacy thing. "The government will track me and know what I own."
Maybe... but even then, it's an item they SOLD, right, so in that case, having something that shows that you sold it would actually be a good thing if that were the reason.
Regardless, like I said above, once something on the internet, it's permanent. Editing their post isn't going to 'erase' it. I can still pull up classifieds ads from the defunct .com site from 20 years ago.
I personally don't want an internet record of everything I have bought and sold.
Hate to burst that bubble, but the moment you put it anywhere on line (nothing specific to this site or any other forum), there is a record it. Editing it, or even fully deleting it 10 seconds later, 10 minutes, or 10 hours later doesn't matter in the least.
It was already leaked that ATF pulls data from forums about gun sales - and it's not some agent in the corner of an office that's visiting popular web forums. The moment you press "submit" to post something to the internet, they (along with anyone else that cares) has a permanent copy regardless of how you edit, modify or delete the original content.
As far as keeping the price.
Most transactions are done in a private message.
What someone ask in their add , might not be what they sold it or traded it for.
That might be, but even then, the posted price is indicative or an approximation of what something sold for and helps gauge what others should consider selling something for.
And feedback is much more useful if someone can actually see what the feedback was for. Was it for a $1500 rifle or a $5 gun part?