Not allowed
Tallness has its disadvantages, as this list demonstrates, but generally, you are not expressly prohibited from visiting anyplace. It may be a little more difficult for you than others, but it is certainly doable.
But in this case, the clearance limit is very clear, and this guy isn’t permitted to pass or enter the garage. It’s a joke, but it produces a nice picture and a clever way to mock how little people pay attention to tall people at times.