Back when I first discovered flightradar24 it seemed like every plane I was curious about came up on there. The curious ones are mostly military planes as they don't follow standard routes and schedules. Then more and more I noticed stuff not appearing. Later I discovered ADSBExchange and things seemed to be on there. But now, again, I regular hear military planes right over my house with not a thing shown on ADSBExchange. I don't think it's a coverage issue as I always see the regular boring cargo planes that come this way. Is it really "uncensored"?

Yes it is uncensored. Starting in 2019, aircraft conducting operations related to homeland security, law enforcement, national defense or intelligence can turn off ADSB out and communicate their location to the FAA out of band.

In sum, yes.

Feed ADSBExchange does not have a good return, ADSBExchange have way less data available, they don’t even have a free iOS client. A single Raspberry pi feeds both FlightAware and Flightradar24, they give you free business plan with apps with good user experience. From a normal user’s point, don’t see a good justification to do so.