If I build a factory at great personal cost, but the materials and electricity to produce the goods cost next to nothing, is it theft if people take these goods without my permission? I don't see the difference between this and intellectual property.
You say it is not accurate but don't provide anything substantial to back up your claim. Instead you use a logical fallacy: because these persons are bad, thus the argument of using term "theft" is bad.
What if someone figures out how to make a similar factory very cheaply, and drives you out of business by only charging their marginal production costs for their widgets? The important difference, I think, is that they're using their own materials and electricity to make their goods, but people who engage in copyright infringement are too.
EDIT: And I'd note that many would would say that this second person is "Stealing the customers" of the first factory owner, but that doesn't mean what he does is actually morally equivalent to stealing.
If they make their own factory then that is ok. Simple capitalism. That is not my point, however. If they use the original factory without paying that is not ok.
You say it is not accurate but don't provide anything substantial to back up your claim. Instead you use a logical fallacy: because these persons are bad, thus the argument of using term "theft" is bad.