Why is that? As a non rated DEC to EZY I had to shut an engine down due to a fuel leak on my A320 interview sim...?! They aren't expecting immaculate flying skills (luckily). If that concerns you too much I’d advise that you’re probably focusing too much on the wrong skills for a sim assessment.
Lots of things you can do in the sim to test a candidate’s pilot competencies in a non-technical way... medical emergencies, disruptive passenger; bomb onboard, weather deterioration, diversions, pilot incap, severe turbulence, blocked runway etc etc etc.
As important as it is, this industry’s focus on SE work is a bit crazy at times.