I wouldn't call it bad intentions. I'd call it being opportunistic or having unaligned incentives. When you own the platform and discovery features (i.e. searc

I wouldn't call it bad intentions. I'd call it being opportunistic or having unaligned incentives. When you own the platform and discovery features (i.e. search), you can create an environment in which your products could be on average more successful than 3rd party products. The calculation to build your own products is probably "is the total value of having a given category of 3rd party products on my service worth more or less than if I build that category of products myself and sell directly to customers?"