Why exactly we can't place stop losses and orders in the pre and post market hours?

Been trading for a while now, in regular trading hours. It's going well and I have everything figured out. But I still can't understand the logic behind extended market hours. I tried paper trading with tradingview and it tells me I cannot place market order but only limit order, even for closing the position. I tried with das trader linked to IBKR and I can place a market order but bracket orders and stop losses do not work.

Can you tell me why exactly? Is there some kind of regulation or rule? I can't really find any satisfying answer. I don't want to trade extended hours, I'm just curious.