It is unnecessary and petty. That's how top tier pricing works here though, someone else saw you potentially making money and they want to shoot you down because you're a threat to them.

But also because you went from paying 300~ to asking 1000, which is quite a jump. People don't like seeing that.

Edit: Plus the showstopper pool party price is definitely a quicksell when there's a buy order at that price, but people just reference the marketplace chart and that's enough proof, quicksells don't exist on marketplace.