Are you a paying customer?
Testers and bug reporters are not paying customers. They are volunteer CONTRIBUTORS.
If so, I understand completely.
Obviously not.
The dev is a bigger volunteer than you.
Nonsense. Contributors are equals. Exceptionally, devs who demand that testers also fix the software are notably smaller (managers, effectively).
And? Of course testers do not pay money. Why would they? Devs do not pay for the tester’s work either. Both developers and testers are volunteers who do not pay the other for their work. On free software projects testers and devs pay with their own labor.
It is not “much larger” for a dev to task the tester to implement the fix. The dev is no more than a manager in this case.