EDITED
cherrybim, there are myriad responsa on the issue of rabbis who are not fully observant of Halacha. The ones that sticks out in my mind are from the Chatham Sofer; one concerning a certain R. Ploni1, the other about Ploni2. Ploni1 comitted various ritual breaches. He talked while putting on tefillin, did not wash neigel vasser, spoke between netilat yadaiim and hamotzi and wrote gittin without the permission of the regional chief rabbi, R. Mordechai Benet. The Chatham sofer ruled that there is no basis to unfrock a rabbi based upon his personal conduct, no matter how offensive that conduct may be (it seems that these lapses, innocuous though they seem to us were a big deal to the community in question). The C.S. recomended that such a rabbi take a leave of absence and carefully think about his life and what he wants to do with it. But writing gittin without proper authorization was worthy of defrocking as such a mutinous act undermined the rabbinic hierarchy and rabbininc authority. The responsa dealing with Chorin deals more with his insiduous influence on Judaism and does not address his persoanl observances with any Halachik consequence.
I’m not advocating that non-religious people be hired as chazzanim. I think all clergy should strive to the highest level of Halachik observance. But the fact that some cantors may have fallen short of the mark during a brief period of our history should not serve as the basis to derisively dismiss the entire field of chazzanut as devoid of religious significance. To do so, unfairly paints the entire cantorate and its history with far too broad a brush.