Quirrel isn’t out and out evil the way Voldi is. He simply invented a larger than life character so that he can play the good guy.
Whether Voldemort’s persona was or wasn’t real, the suffering caused by him was real.
If I would for some reason decide to pretend that I’m Voldemort, and I would kill many people (shooting them by gun while pretending to cast Avada Kedavra), finding out this all was a disguise would prove that I’m not Voldemort, and that Voldemort’s professed beliefs don’t have to be my actual beliefs… but I would be a horrible person anyway.
Whether Voldemort’s persona was or wasn’t real, the suffering caused by him was real.
If I would for some reason decide to pretend that I’m Voldemort, and I would kill many people (shooting them by gun while pretending to cast Avada Kedavra), finding out this all was a disguise would prove that I’m not Voldemort, and that Voldemort’s professed beliefs don’t have to be my actual beliefs… but I would be a horrible person anyway.
It depends on what your reason for adopting the persona in the first place was.