The "it's not theft" argument is pedantry. There are lots of ways to obtain things for free that aren't technically theft: extortion, blackmail, fraud, etc. Illegal copying is one of those ways.
Disagree. Even in the extortion, blackmail, and fraud cases, you're removing ownership when you obtain the thing. Copying never removes ownership, so it is not in the same class. It is not theft, and it it not pedantry to claim it is not. It's incorrect to state it is something that it is not to make it sound worse than it is.
I would guess that it's at least a strong minority view -- if not a majority view -- that record labels have abdicated their moral authority to assert transgressions of this kind. It is not unlike patent trolls, where we feel that if someone fails to capitalize on a potential market and in fact attempts (politically, legally, etc.) to hinder the growth there, that they forfeit their right to be wronged.
So I think it's a shame that both sides never seem to get around to Step One, which is to say, "here's what I think the spirit of the law is, here's what I think the purpose of law as a whole is; now, do these conditions efficiently uphold those ideals?"
If those questions are answered then it may not be "pedantry" -- perhaps they think that the purpose of the law is to stop theft, and theft-like deprivations of property. There may or may not be a nuanced argument here; and we won't know until people manifest their assumptions rather than burying them under knee-jerk slogans.
Libel/Slander? Trespassing? Vandalism? Disobeying zoning laws?