I shouldn't have to remind people to take off their shoes when they enter my house, do you agree?
Why do you insist that people take their shoes off automatically as they enter your house?
It's a rule that I've set for my house, I don't want dirt to be tracked into my home.
I'm sure you want to keep your house clean but you have to remind people about the rules you have for your house. You can't expect them to remember the rules so a gentle reminder when they enter your home would be appropriate.
They have to remember, otherwise they don't have to come over.
It's fine to have that rule, but reminding them isn't really some great burden on you. It makes things smoother and eases tension when everyone knows what's expected of them.