I've worked (very recently) with some really horrible programmers..real phonies. It isn't ok, they deserve to get fired (quicker than they did), they are easy to spot, it's a major flaw that they got hired in the first place, and a bigger one that they stick around for months.
It drags everyone down..it can kill a team and certainly a project. It's a major reason I quit.
It sounds like a different degree of phony. Phonies are all over the place and show up in many social situations. Many times it arises due to wanting to fit in.
In my weekly RPG, we had a new person join who claimed some experience with the gaming system, but didn't oversell herself and was eager and knew her competencies well enough to pick it up fairly quickly. That's pretty much the trick. Too bad the phonies you encountered (it sounds like) oversold themselves too much and couldn't keep it up.
It drags everyone down..it can kill a team and certainly a project. It's a major reason I quit.