Earlier quoted context omitted.
The tu quoque fallacy [1] is not proof. Stealing IP without contributing to creation costs is bad behavior on several levels. [1] https://en.wikipedia.org/wiki/Tu_quoque#The_fallacy
You assume that "IP" is a real thing. It is an invented concept. Those who insist on its reality do so for their own benefit. Those who deny it, do so for their own. How are disinterested parties to decide? Well, they might examine how genuine the two positions are... There is a difference between "I can do this bad thing, because you have already done it" and "this thing is not bad, otherwise you wouldn't have done…
And no, tu quoque definitively intends to discredit the opponent's argument by asserting the opponent's failure to act consistently in accordance with its conclusion.
This applies to whataboutism, and exactly what we're talking about in this thread of deflecting back to the U.S.'s inconsistent behavior in the past.