The thing is, you can always dig up some hypocrisy if you go back far enough. Our ancestors doing something bad doesn't forever nullify arguments against other people doing that thing to us. You don't deserve karmic retribution because of what someone else did, even if you benefit from it.

I would discount the validity of advice to stay away from performance enhancing drugs from someone who uses them. I mean they're right, but I don't feel... inspired to do so.

There are other ways to convince people, like appealing to their interests or punishing with retribution.

And also given how IP is abused these days much more than it was in the past, which weakens moral arguments in its favour.