As I asked upthread, if a public university chooses to charge one favored group of students les for the same education as everyone else would you object to calling that a subsidy?
If not, what's the difference between that and a state choosing to charge one entity less in taxes than the others yet providing them the same level of services?
No.
But; businesses WILL 'charge' whatever the market will bear.
GM will take a Chevy pickup; plunk GMC logos on it, call it PROFESSIONAL and charge MORE for it because there are some customers that perceive a greater value in what they are buying.