Things aren't only bad if they're illegal. There's plenty of bad things one can do that are perfectly legal, and plenty of good things one can do that are totally illegal.
And there are legal remedies to create deterrents without a court. Boycotts, journalism or new competition.
It's not clear to me that causing "financial damages" to the person described is even a bad thing.
If you prevent your grandparent from getting scammed, you've caused financial damages to the scammer.