It’s okay to shame smokers because they are hurting more than just themselves with second hand smoke. But it’s not okay to shame fat parents who let their kids get fat even tho that’s hurting others. The logical conclusion of what you’re asking for is absolving people of accountability for their poor life choices. People rightly and understandably vehemently disagree with this.

Shaming works. There's nothing wrong with doctors telling overweight patients to lose weight. Because it is unhealthy.

It's obviously people who like being ashamed! /s