I remember having a discussion with the ceo of discord on their api server. The statement was something of "we will never sell user data". But our points of "okay but how about when you sell discord?" fell on deaf ears.

Discord does not allow you to delete your messages in mass. If you exit a server all of your messages, images, etc, are still there. Even if you delete your account. Servers can only delete up to some X amount of time if they choose to.

I have no doubt that just like facebook buying Oculus the promises of any sale will be voided in the name of money.

We have to remember that when you build products with other people's money, that money has to come back, and it has to come out of it's users somehow.