Probably because the cheap chinese radios don't have to meet any spec or standard that public safety radios need to meet. And, if you're not used to listening to digital, it does sound different. Decades ago people complained about how SSB sounded compared to AM.
Can anyone else weigh in on how "really bad" Cranston FD sounds? I have absolutely no problem listening on multiple radios and scanners.....From a cheap 996T to an APX8000 all band portable to an APX8500 all band mobile and a bunch of low to mid-level Kenwood and Harris public safety radios.