Would I be a bad person for not calling out my supervisor for being disgusting?

[Anonymous]

I started working for a cleaning company that has contracts cleaning a lot of office buildings. My supervisor was training me and I watched him clean one of the restrooms. He used a rag to clean the toilet and used the same rag on all the light switches in the office. I'm afraid to say something to him because im afraid he might get angry. Would I be a bad person if I said nothing?

[devilish-cutie]

maybe first try to suggest another solution instead of criticizing him
eg. should/could i maybe do this and that instead of that? cause of this and that?