And this is different from bying more efficient ASIC hardware ...how?
This is different than buying more efficient hardware because I am free to buy the hardware from any vendor I like, or create my own. There's no law telling me that if I want to use the more efficient mining algorithm I need to gain permission from a particular person.
"a patent troll is a person or company that attempts to enforce patent rights against accused infringers far beyond the patent's actual value or contribution to the prior art"
In this case the idea being patented is the that of not repeating the same calculation multiple times. It's hardly a novel idea. Requiring a licence before allowing people to omit repeating the same calculation multiple times isn't right.