Even if Ron begrudgingly thinks Leslie did a good job with the local department that doesn't translate into him now admiring (or at least tolerating) the National Park Service, which seemed to be what he was saying.
I think that's being a bit ungenerous to Ron. He still hates all government departments, it's just because he works in Parks and all his friends work in Parks and Leslie is a force of nature that not even Ron can deny the power of, he has to concede that, of all the government departments he hates, he hates Parks the least. You have to admit, if you asked Ron which department he hated the least, that he would say Parks.
Good point. Perhaps the issue here is/was confusion on my part. I thought Ron was taking about the federal parks agency. Other posters seem to think he was talking about the local one. If he was talking about the local one it makes more sense to me.