I think it's naive to frame it as "wanting to give data" but more that they're allowing themselves to be exploited because many simply don't even know what's in the policy, there are many who concede that they can't do without the platform, and then simply folks who don't know better. I highly doubt there's any significant number of people who understand the policy and happily consent even if they could easily give up the platform instead.
So I think they're both problems. A platform needing data beyond what's necessary to provide the service AND that most people will either concede defeat or not know better.