It's not stealing. It's copyright infringement. Yes, it's illegal, and (usually) should be. Yes, it's (usually) wrong. But it's still not stealing, and yes, the distinction does matter.
Right. Steal something $100 and it's petty theft. "infringe" on some copyrighted software of the same value and it's a federal case.
A computer scientist is someone who fixes things that aren't broken.