it doesn't. if someone else mines a transaction with an ordinal, your knots node will process it. you would have to kill everyone on the whole planet who doesn't use knots for the stupid filters to work. all they do is let you ignore the transaction until it gets confirmed, causing your fee estimation to be incorrect all the time. once it's confirmed you can't ignore it anymore.
you can try to make things like ordinals and large op returns actually invalid by forking bitcoin, that way they will never get confirmed. but people will revert back to stamps, which you can't make invalid. the only way to totally stop people from making valid transactions you don't like is OFAC compliance at the barrel of a gun. this is a clear example of people wanting to have their cake and eat it too. if you are bothered by permissionlessness and any degree of arbitrary data storage, stop using all forms of cryptocurrency.