The problem with canon is that its meaningless when applied to a TV series.
Continuity is vital for story telling and suspending disbelief, but trek is so riddled with contradictions, continuity errors, plot holes and terrible writing that any idea of Star Trek Canon is pure fantasy.
To see this fantasy defended and guarded with such passion really does frustrate me because its misguided and futile. We have a right to expect continuity from one story to another, but there is no fact, no truth, no canon of Star Trek. Its just TV.