[dragonwriter]

> What happened to ‘innocent until proven guilty’?

It applies to criminal punishment, and nothing else.

> Are mere allegations enough to lose your job?

That depends (here, where the “job” is almost certainly an explicit contract, not at-will employment) on terms of the contractual relationship, but its very common for contracts to have termination clauses that don't require a criminal conviction. (They may or may not require some payment.)