The rule states that the runner must be given a clear path TO the plate.
Naylor certainly had a clear path TO the plate. Not that he would...or should...but he could have reached the plate by sliding. There was nothing there to impede a slide.
In the replay officials opinion, Hedges had the plate blocked before having the ball, leaving no path to the plate. Thats a totally subjective call, which is open to debate. The runner could have slid from the backside....which is actually what he did.
Its a bad rule, but its a rule with an understandable reason that both MLB and the PA agreed to.
How many instances, like Rose-Fosse and Leron Lee-Carlton Fisk, are worth a bad rule, meant to ensure that we don't see another?
I saw one on TV and one in person. Neither was pretty.
There have been other rule changes, also meant to protect defensive players. A baserunner can no longer go into second base wide with spikes up to break up a double play. Ty Cobb and Frank Robinson probably still bemoan that one.
(I was very good at that, too. Led to more than one...uh...physical misunderstanding...lol.)
Pitchers can no longer purposely throw at batters, esp above the waste. Pedro and Bob Gibson hate that one.
There are some who think those are bad rules.
But they are the rules.