I have never understood the antipathy some Orthodox and Catholics have to CCM; I can only assume such antipathy is created and fostered by Evangelical converts to Orthodoxy or Catholicism who want to distance themselves completely from their past. Some CCM is complete and utter crap. No one with half a brain cell denies that. However, much is also quite good. In that respect, it is the same as any popular music: some of it sucks, some of it is good. I mean, bands like D.C. Talk have even had their music played on VH1 and MTV (in the case of D.C. Talk, shortly before they went on an indefinite hiatus, their song Between You and Me was making the rounds on said stations, and on popular radio). Then there are bands like Switchfoot which are composed of Christians and write songs that seem to quite clearly be influenced by Christianity, and who are quite popular nonetheless amongst non-Christians. However, bands like Switchfoot usually get ignored by those who attack Christian rock for no apparent reason, because Switchfoot doesn't make any major attempts to tie itself in with the Christian music industry, whereas Toby Mac, for instance, does.
As to the charge that CCM is not, somehow, "theologically heavy" or some such thing, should you really expect it to be? I mean, when CCM artists create songs that they intend to be worship songs, they usually take a piece of the Psalter, sometimes a whole Psalm, sometimes not, and expand it into a 3 to 5 minute song. If anyone attacks CCM for not being theologically heavy, they must attack David for not having put enough theology into the Psalms, because most CCM is at least as theological as the Psalms.
As for Christian rock specifically, it seems to be that most people have one or two songs in their mind, and listen to every other Christian rock song with preconceived notions that it must be a "Jesus-is-my-boyfriend" song, and then keep hold of lyrics that they can interpret that way, while ignoring the lyrics that contradict such an interpretation. Honestly, I've quite seldom heard a "Jesus-is-my-boyfriend" song, and I spent the better part of a few years listening to more-or-less ONLY Christian radio stations (specifically, KLove and Air1).
As to the accuracy of the theology that is in Christian music, well, most CCM songs COULD be interpreted in theologically flawed ways, but COULD also be interpreted in theologically accurate ways, much how Amazing Grace can be seen as endorsing once-saved-always-saved, or can be seen in a theologically accurate way. Those who are not prejudiced against Christian music will not hear every single CCM song as being heresy, while those who are prejudiced against it will always hear it as the gravest heresy.