There's nothing like a title almost everyone disagrees with. It's a sure-fire way to make sure people at least look at the article. So, now that you're looking, I'll be more clear. If you're interested in actually improving your climbing ability, you'd be wasting your time if pull-ups were a major part of your training. It's not that the movement is inherently bad, it's just not specific enough to what we do on the rock to justify spending valuable training time developing it.
Think about it a little. The pull-up is biomechanically a "vertical pull" movement, one where resistance is encountered along the same vector as the vertical torso. When this vector is encountered in the real world it's on vertical or slightly less-than-vertical rock, a situation where (if you're any good at all) the much stronger legs are doing most of the work.
When rock gets steep (and routes generally more difficult), the vertical pull is vastly diminished. Rather, the movement of the arms becomes that of a horizontal pull, or a rowing motion. Force is directed perpendicular to the torso, and the use of the legs is somewhat compromised. In climbing, this scenario plays out multiple times on each route. Try this: set up an Olympic bar in a rack and do a horizontal pull-up a.k.a. inverted row (like in the photo below, except with your shirt on. When you get to the top, release one hand and see if you can hold the position. If you can't...well that's something you can work on that really will help your climbing.
Now, think about this: Its rarely the raw strength of the lat and arm that fails a climber anyway. When a climber can't pull a move, more likely than not its a neurological inhibition of that muscle group, which can't be overcome no matter how strong your pull is. Since the nervous system will only "allow" the body to work up to the strength of its weakest link, the hand (and the hold it is using) determines how much you can actually pull.
Now lets talk about time. Unless you're some rich trust-funder sponsored by The North Face, you probably don't have a lot of it. With a sport as complex as rock climbing, building raw strength in an arguably non-specific movement should be considered a waste of this resource. Outside of general work capacity training, then, we can see that running, weight lifting, and the like are not good uses of our training time. Climbing is a performance sport and the only measure we really use is how well a climber performs. It's not like we're all sitting around the crag watching some dude flail on "The Madness" thinking, "Wow, he sucks at climbing, but you should see him do kipping pull-ups."
I'd venture to say that anyone who even talks about how many pull-ups they do is trying to cover up for knowing their climbing is weak in a major area. It's like the crappy father who always counters with a comment on how much money he makes...lots of dough, still a shitty dad.
The advice always goes the same way: assess what's really holding you back, and get after it. 999 times out of a thousand, pull-ups won't be on the list.