with intent to deprive the rightful owner of it
this is also necessary condition for 'theft' in about any legal code. this condition is not met in this case, and unless you can prove it is, your discourse just doesn't stand.
if you're betting on 'loss of rightful revenue', it's a skewed and controversial concept. the problem here is the term 'rightful' which is a nebulose trying to coerce 'their right to sell' into 'my obligation to buy'. needless to say, i don't buy it. but even then, assuming some imaginary context where that 'rightful revenue' really existed ... you can't 'deprive' someone of something they never had. so without deprivation it can't possibly be theft, and i'm not a thief. you should be really able to grasp this simple and fundamental fact.
call it something else. take your pick, i don't care. but calling it theft is irrational or dishonest or both.