Renoir's impressionist style and brush technique is very different from Rubens's baroque style and technique, not to mention 300 years of distance between them. That's plenty of time for tastes to change. The point of all the cellulite and dappled buttcheeks in a Rubens painting is just to show off his technical prowess and capturing those details. It's sort of like the difference between heavy camera filters and HD TV, everyone looks good with the former, and everyone looks hideous with the latter.

But hey, not everyone has to like Rubens. I just think he deserves a little more respect.