Not at all, in my opinion. I suppose if a guy were really into rears, he might not notice the rest ... including how hawg-stupid she apparently is.
In the past four decades of my adult life, every non-homosexual man whom I've discussed the issue could fairly be said to be "into" nicely shaped female rear ends. Not even bosoms catch our attention the same way, and the best part is you can appreciatively ogle her from behind for quite a long while without her knowing. Do we deserve feminist ire for this? Don't think so, but don;t care.