I think the point is not that the core domain can't fingerprint you, it is that 3rd party JavaScript is blocked by default, which makes those domains less likely to track you. Not impossible, just less likely. For example there is almost never any reason to allow Google Analytics JS.
Agreed. If you take the default uMatrix setup, change javascript to be disabled, then just whitelist as you go, you'll pass most of those tests and be pretty tracker-resistant.
My suspicion is that fingerprinting by the core domain will actually get worse since your browser behaves so differently from stock browsers (which is after all the point of uMatrix :-) ). The majority of trackers tho will be third party (such as Google analytics). Very few sites roll their own trackers because it's hard to get right, and some great ones like GA is free. For those that do, I'm not too worried anyway, but that's certainly just a personal thing.