Why do people get so upset if you try to help them with car seat safety?

T🌸
Genuine question, no need to get your panties in a wad over it. I've just noticed many mothers will get extremely upset if you try to help them with their child's car seat, like if it's not buckled correctly or if they are forward facing too early. Why get so upset? I know everyone says the whole "mind your own business" thing but I think this is too important to do so. If I was using one wrong and someone passed along important information, I'd be thankful for them doing so! It can mean the difference in life and death in the event of an accident. Thoughts? Be mature and polite please. I know car seat safety gets everyone tore up 😳
Updated to add: I know someone will say "we all parent differently" but I don't think that applies here. There is a manual with the car seat so I would think what it says to do would be the right way no matter what your individual parenting style is.