I think the issue should not be how we have to handle toilet breaks. BTW my company always required a F/A to cover the seat of the pilot who takes a leak, and am happy with it.
The issue is rather who is allowed these days to be at the controls of a big airliner. Being very young/inexperienced, like this 600hrs German, does not produce a long list of references/reputation an employer could take advantage of before hiring someone. Yes one may pass all tests for a flight license, but we all know that pilots nature is quite good in hiding problems.
Just my 2 cents..