Shareholders also don't care if the behavior continues so long as the profits from the behavior continue to vastly outweigh the cost of the activity in question.

If the fine is $ABC, and that fine never changes, but profits grow from $ABC x3 to $ABC x10, shareholders will actually get mad that the corporation doesn't continue the activity in question because there's net profit growth.

Sadly, sometimes the cost of quelling an FCC or SEC violation charge is simple "lobbying".