They where NOT preventing anybody from operating on any spectrum they wished, you could walk outside of the venue and crank up your WiFi hotspot anytime you wished. Private property owners have the right to allow or deny any activity on their property they choose
C'mon, that's so obviously not true I'm not sure how you finished typing it. Anyway, the airwaves are special. You can't charge a fee to have access to them on your property. (So many things are special that it's hard to think of them as special cases these days - there are exceptions to just about everything you wrote - for example, you can't make rules that have the effect of excluding black people from your property. There's lots of case law around dress codes.) Excluding is different from restricting to only those who pay a fee.
If we don't have such property rights in this country, then why do we call it "private property"?
Conservatives asking that for years now. Just try creating a pond on your property!