Yes, you are right. But the distinction that should divide trolls from non-trolls (at least, as much, as the big corporations wanted) was mainly, if a company produces something related to the patent. And that is in my opinion the worst classification you can find (it is handy of course for the big corporations).
- trolls usually aren't the original IP creator,
- trolls' patents often cover trivial material, or ideas which are included in prior art.
I'm gessing that ARM patents are not trivial.