I think the rule is poorly written. As the TV crew explained the rule the umpires applied it correctly which is their job. They don’t have the liberty to change the rule on the fly, even if it flawed. It happened so fast that I don’t know if Royce tried to put his foot there or it ended up there because he was tracking the incoming ball. The really crazy part of the rule is no provision for which base the runner is trying to obtain but again the umps can’t change that.
One point of clarification on Clemons baserunning. There is a set play where a runner rounding second will hang himself out to dry in order to get the cutoff man to cut the ball and let the runner score. Essentially you are trading an out for a run. The mistake was that you only use that play when the runner is likely to be out at the plate. It appeared that Keaschall was going to score so it was not the correct time to do it. Kody correctly got himself in a rundown so Royce could gain second base. Or he could have screwed up by overrunning the base but it appeared that he did it on purpose - I guess only Kody knows. Teams don’t seem to use this play as much anymore.