I think it's easier for a person to say "piracy is bad" than "sharing files is bad". Because why would sharing be wrong? But if you give it a bad name, a lot of people will automatically assume that it is something bad. It's a simple trick, but it works. If we want to change the way people think about copyright, we shouldn't let anyone imply that sharing information is the same as stealing ships and murdering people on them.
While I agree about reclaiming the word, what OP is talking about is not what a reclaimed word accomplishes. A reclaimed word is about empowerment within the group. OP is talking about selling the concept to the public at large. I think if people in the filesharing community want to use the reclaimed word “piracy” in private then they should go right ahead. But if someone has the goal of viewing this as a justified act, then calling it “piracy” in public spaces undermines that.