Why does acne bother people so much

I’m writing this as someone who has mild acne but a bunch of scars but more for the way people treat my sister who has a little more “severe” acne , but to me it’s nothing so serious to come up to her and give advice, recommend their own soaps and other products. It’s actually starting to piss me off . They approach her while she’s at work or just out in public. She’s a little more on the shyer quiet side so if any ways that have help you avoid these situations and could help her out would be great! I want her to be able to say NO to these unsolicited advice and comments