OK, let's run a scenario.
You're in Huntersville, and you're selling a HiPoint thats worth $140. You bought it for $100, and post it for $130, expecting to sell it soon at a decent price for a $30 profit.
Three people say, "I'll take it."
The first guy to say "I'll take it" has no reviews, joined yesterday. Lives across the state in Waynesville. Says he is not willing to drive to Huntersville. Should you be forced to drive four hours to sell a pistol? Lose all your profit in gas, maybe even end up losing money?
The second guy lives in Raleigh. Says he will only pay you $120, but will meet you halfway. Should you take a $10 hit and drive an hour to meet the guy, if you don't take the first offer?
The third guy is your friend, you've known for years, and you're meeting him for lunch next Tuesday anyway.
Why should the seller have to sell to the first guy, or the second, just because someone said, "I'd like to buy it?" It is the sellers property, and he has the right to sell, or not sell, to whomever he wants.
Yes, when a seller says there's in the background bidding I find that unsavory. I wouldn't do it, and wouldn't trust anyone, either a seller, or a buyer, that would attempt that. But I don't think it's a good idea to limit the freedom of others to what is basically a glorified "first! " post in a YouTube comments section.