They don't have to. It's their money, their rules, their ways of following them. You just cannot argue with that.
If you comply and get lucky, perfect. If not, move on. That's what I've done. And many others too. There are more campaigns, there are more opportunities, and it's not all about money.. or should not be.

Now... if Chipmixer would also pay 25-50$ per week, would you care?