I think part of it may be price discrimination. The customer that comes to your site directly already has your hotel in mind, and is probably less price sensiti

I think part of it may be price discrimination. The customer that comes to your site directly already has your hotel in mind, and is probably less price sensitive, so you fleece them. The customer that goes to the aggregator is more price-sensitive, so you ask for a lower price in order to get at least some money out of them.