While true, I suspect we're eventually going to have to change to not modifying the resistance display int he character panel when you become immune. It's only a matter of time until there's some effect that scales based on the actual value (or uncapped value) of your chaos resistance, and thus means it's important to be able to see that value - or likewise an immunity to one of the elemental damage types, since those already have things that scale on resistance.
Ideally, in such a situation resistance would not be displayed while immune (there would instead be a specific line saying you're immune), unless you also had some other stat that scaled on resistance and made it display the resistance values so you could see them (alongside the immunity).