I would hope that this kind of incident would never be judged as anything but 'extraordinary circumstances' and that no compensation would be payable under EU261. If compensation is claimable then it has terrifying consequences for inflight safety for all flights that come under EU261 in future as airlines will simply take the problem into the air or may feel pressured into continuing despite a potentially unsafe situation in the cabin.
We don't know the circumstances that lead upto this individual acting in such a way. But regardless, the decision to remove him was the right one. How that is achieved (persuasion, force or taser) is for the police to decide, and certainly not the airline nor the crew.