Plus algorithms suck there.

It unironically is, and it's not entirely the fault of the users either. The average person doesn't know what FOSS means, what instances are, or what a federated service is and many platforms do a poor job of explaining what those things are and why they are superior.

Additionally, people need to understand that FOSS is not a selling point to the average user and that throwing that term around will go in one ear and out the other. As far as they are concerned their apps are already free because they don't have to pay a transactional monetary value for them and "open source" is beyond meaningless to them and they couldn't care less.