You don't seem to get eXch doesn't choose which trade their customers make. The customers do.
As the largest XMR exchange in the world (according to them), it has many options. But they decided themselves to be empty or semi-empty for a long time. Zero or ridiculous coin supply. They decided they would rather have millions dollars in coins that could be bought anywhere else in the world. It's all weird.
If I have to make an order, I prefer to use a normal CEX, for example TradeOgre or another. I don't have to go to an instant exchange.
I'm just an ordinary customer who wants to buy coins. Nobody pays me.