Liam,
I agree management bonuses aren't related to profit share. You and I can see that but ask someone on a service desk or a ground engineer or any other "at the coal face" and see what the concensus is.
The managers are payed what they get paid period. What people find hard to accept is the amount of bonuses that managers get paid. This is not a Cathay problem it is a global problem that all large companies are having trouble justifying to not only staff but shareholders and the general public.