“However, the cop did nothing wrong”
Disagree. We’re not talking about a cop walking in on a robbery or even responding to a complaint (the cop said he was there ‘randomly’).
Without any probable cause, there is no reason for him to draw his gun. If I did this, it’d be called “brandishing a weapon” - and that is only one thing the cop did wrong.
I think he only needs reasonable suspicion, which from a practical standpoint means just about anything.