So you think that if e.g. Stack exchange is storing code examples in their database, they shouldn't transform the special characters into e.g. url-encoding or s

So you think that if e.g. Stack exchange is storing code examples in their database, they shouldn't transform the special characters into e.g. url-encoding or some other escaped format? How are you going to validate it doesn't do something harmful? And also, you keep mentioning sanitization as though it's not inherently a transform. Stripping out whitespace? That's a transform. Just because it's a one-directional transform doesn't make it not one.