Because we bow heavily to media and public image pressure would be my main guess. I do think we could of taken far better courses of action than a straight sacking. Though if the whispers of rumours are true, we may have already tried those courses, as he had been running amok for a while.
I'm not in the know, nor living near the Shire. So my knowledge of what he has been up to, and what we have done is limited to what is revealed on here.
If it wasn't for here, to me, this would appear a complete knee jerk reaction to a minor and victimless idiotic moment that couldn't damage the brand anymore, just delay any rebuilding of our image slightly. Which without a star performer going forward will be just as hard.