So here’s the thing about headcanons (because some people don’t seem to understand this): they’re not canon. They don’t even have to have a basis in canon. They’re literally just opinions. 

Headcanons can be based in canon events of a piece of media or they could be completely made up with no textual basis whatsoever, but either way, they’re not facts. Headcanons are just fun ways that fans engage in the material. 

If you don’t like someone else’s headcanon… good for you? If someone offers explanation for their headcanon and you don’t agree… okay? The existence of a headcanon is not a problem. What is a problem is when people with certain headcanon try to push them off on other people and get mad when you refuse to adopt their opinions as your own. But if people are just minding their own business, enjoying fiction and relating to it in their own ways it’s not hurting you.