It’s possible that she doesn’t want them misused by someone else...
I wouldn’t be surprised to find that she didn’t come up with this callous idea on her own-it sounds more like something “reverend” Sharpton or his coterie of race-baiting vultures would invent to keep the money rolling in.
Your explanation is plausible, not the only possible explanation but one that does not require twisting logic or our knowledge of human nature. Just as I hope that people would wait for the facts before judging Zimmerman, I hope that we will wait and see before judging the mother.
Very open-minded of you to think of that, and it is quite possible.
My best guess would be that the family was assigned a lawyer by the arms of the DNC/CBC and that the lawyer advised the family to apply for the trademark patents.