No IP violation is a theft unless it involves "a person intentionally takes personal property of another without permission or consent and with the intent to convert it to the taker's use".
It's a violation of copyright, trademark, trade secrets, counterfeiting or patent, but it is not theft. The usage of the verbiage "theft" started in the late eighties to early nineties as part of a campaign to make intellectual property violation sound more severe than it actually is.
The key difference is that, by depriving another person of their property, you are preventing them from using it, where in intellectual property violations, you are merely gaining use without denying use to the creator.