Those arent excuses... more or less facts.
A. You have not yet shown that half the community does it. It is not a fact. Nor would it matter even if they did. Half of the population doing something wrong does not make it right. Therefore you are using this as an excuse to get us not to pursue longer ban times. If that is not your intention in citing the so called fact then what is your intention?
B. The "why dont' you leave" excuse is just that. It certainly isn't a fact as it is a suggestion, not a statement. It is just your way of saying you could care less about cheating--ie you are excusing it. Anyone who doesn't share your carefree attitude about cheating should move on. That is an excuse.
C. The not everyone knowing is not a fact either as they have had opportunity to know. If there is not enough opportunity then that can be addressed through practical steps. So again it is NOT a reason to not pursue long ban times.
A reason to not pursue long ban times that would NOT be an excuse is one based around an ethical argument discussing the moral ramifications. Deranged attempted this. You started to before offering all these excuses. But since no one can provide a great ethical reason why removing rights to a video game is a an in-humane, horrendous punishment we are left to the same old excuses.
Another possible objection, attempted by Jits, is a practical one. But if it can be overcome then the objection is no reason not to follow the longer ban times.
It all comes down to this--people AGREED not to hack. If they do hack they have no excuse and no reason to whine if they are removed from the game.