I wont cast a judgement one way or another on how to approach this, but just know that it is an incredibly common rule. Every girlfriend I had growing up had this same rule, or even more strict. For one I wasn't allowed in her bedroom at all when I came over.
It sounds like your parents are perfectly including your identity in their decision. I know from experience that the rule sucks, especially when you aren't even planning to do anything and just want to hang out in a comfortable space. But it is common, and quite reasonable considering how other parents might approach it.