They built something amazing and now have a nice exit. The code remains open under a non profit foundation. I don't think it is that bad. If working conditions are too bad people will just quit and work for the foundation.
You make it sound like every worker agreed with this. Is this actually true or is it more about the founders exploiting their workers by selling out to one of the most devious anti-worker tech corporations?
Is profit sharing, like what you're implying, actually happening? If so, in what quantity?
An exit can be a nice payout, but only retirement level payouts for a very few. Most will need to find a new job and the market is pretty shit right now and I doubt the foundation has the funds to hire the entire team back.