Unwanted help

Went to the gym today, finished cardio and started with weights. I was busy with my set, when a trainer just approached and said I'm doing it wrong, and started touching me to show "which muscle I should focus on", without my consent. I didn't ask for any help. Then he tried to show me what other exercises I rather should do. This is where I said no. I already have another trainer's schedule, but didn't feel the need to tell this guy my whole story. Why can't we just gym in a secure and safe area without people approaching you. Does that even exist anymore.