Somehow this has become a "thing" with ATC. All PA28's are Cherokees.
It is because someone got uptight about all the different Pipers that
were PA28's (the ICAO Identifier), but yet named differently. You use
the ICAO 4 letter ID (all aircraft have one, and only ONE), on your
flight plan, BTW. But it seems that one ICAO identifier can encompass
many different aircraft names. Thus the confusion. The Cherokee one
seems to be the one ATC keys in on. Must be the one they use in their
training or something.