The argument against PhoneGap seems to be either that there isn't a place at all for such a technique, or that people think the benefits don't outweigh the drawbacks. Another option is that people dislike the developer accessibility aspect out of pure snobbery.
However, I rarely hear people making these arguments. I just hear (not necessarily in this thread, but in previous ones) "blah blah it sucks blah blah why not write native code blah blah".