Hard to say. The TV/radio stations could be putting out spurious signals on 72 MHz, but it also could be that the TV/radio stations are operating properly but overloading the front end of your R2, or that your R2 has image frequencies that fall onto the TV/radio stations assigned frequency. The fact that you say dual conversion RC receivers have minimal problems suggests to me it may be one of the latter.

It certainly warrants further investigation. I'd say ask around at your club or maybe visit the local ham radio club. There may be an electronics guru who has, or have access to a spectrum analyzer. That will provide a more reliable picture than the R2.

If the stations are putting out spurious signals 72 MHz then they have an obligation to fix their problem.