I've never really had conversations with anyone knocking Ringo. I personally enjoy his playing, and love the Beatles in general. My friend Johnny, who's a drummer (also a big Ringo fan, and a Beatles maniac in general - even played in a Beatles cover band for like 6 years), put it like this: "The question you have to ask yourself is, would people still rate him as one of the top rock drummers if he hadn't played with the most popular rock band of all-time? If Ringo had been playing with a band that only a small number of people knew about, would the people that knew about the band be saying 'Hey man, you have to check out this drummer, he's one of the all-time greats!'? Highly doubtful. I love the Beatles, and I love Ringo, but when somebody asks me who I consider to be one of the all-time great drummers, I have to put my favoritism aside and be able to look at a musician for their abilities, even if I don't particularly care for their playing."
I think he makes a very valid point in his assessment. When calling a musician one of the all-time greats, we have to be able to put our favoritisms aside, and look at their skills.
Probably the harshest comment towards Ringo that I ever heard came from his own band mate, John Lennon. Lennon was asked by an interviewer if Ringo was the best drummer in the world. Lennon replied "In the world? He's not even the best drummer in the Beatles!"
Unfortunately, a musician's popularity can sometimes cause a backlash by others. I think that's the case with Ringo. His popularity doesn't decrease his musical abilities, but unfortunately some people treat it that way. It's one thing if you think that he's not one of the all-time greats. It's another thing to have a "he can't play" attitude simply because you feel like he isn't one of the greats. Sadly, a lot of people take the latter road. If somebody doesn't care for his playing, or doesn't consider him to be one of the great rock drummers, that's fine. But to say that he can't play is just ridiculous.