To me at least, the "issue" of which rule should apply to what Mickelson did is mildly interesting, and nothing more. I think the point of the confusion over which rule applies comes out of the fact that the Rules don't really contemplate situations like this, so that neither applies perfectly. The Rules are meant to cover situations that arise in the more-or-less "normal" play of the game, not an entitled asshat having a nervous breakdown/pity party at the US Open, and then lying about it on national TV.
What IS interesting to me is the reveal of Mickelson telling fans who had a problem with what he did to "toughen up". This a guy who gets to play golf for a living telling everybody else to toughen up? There is a part of my anatomy upon which he may plant his lips, now and forever. The last thing in the world I need is somebody telling me to toughen up; I'll swap problems with him ANY day, and that's without even knowing all of his.
I've never understood the guy, but there were a lot of times that I admired how he handled adversity. No more. I felt bad for him missing out on the career slam with six seconds in the US Open, but no more.
I'm going to go one step farther and just say that I hope the guy never wins another golf tournament. So that he has to, you know, "toughen up".
Jeez...