Re: Mercenary Supervillains
What he said.
It is a common trope in the comics that heroes do what they do out of altruism, with no expectation of any compensation. This is well and good if a hero is capable of supporting themselves through other activities. But if someone has super abilities, using them on behalf of an employer, or as an independent contractor, should be too far beyond the pale, so long as the activities themselves are not criminal.
Granted, wearing a costume, acting as a superhero, and shilling for products tends to grate on a lot of people's nerves; see various incarnations of DC's Booster Gold for an example. OTOH, licensing merchandise and getting a percentage of same seems to be acceptable, much like professional athletes in the real world. The basic idea is that A. there is a demand for merchandise associated with the hero, B. it is assumed that the hero owns the rights their own public image, costuming, etc. and C. licensing those rights is acceptable.