Yeah, I think it is as nonsensical a model as you can get as it's based, for the most part, on ESPN's garbage RPM stat
Vehemence, or just rhetoric?
No, not garbage. Can't tell what your objection to it is - perhaps valid, but it hardly seems likely that it would justify dismissing the stat entirely, as you seem to be doing.
Its big virtue is that it controls for who else is on the floor - that's a big step up from ortg and drtg, and from the raw +/- that you get in the box scores nowadays.
My own objection to it is that using box score priors biases it in favor of players who get more of the countable stuff in the box score.
Like any statistic, it isn't the whole truth about a player - what you might call the Siren Song of the Single Statistic.
What I like about it most is that for certain players it suggests surprising or provocative things. It doesn't like Klay's defense very much, for example, despite conventional wisdom. Then you can ask yourself, well why not? And look for yourself.
The big problem with all the different types of statistics, including the various flavors of plus/minus, is that the sample sizes are seldom big enough, while the sample sizes for the different players vary so widely.
(which could be Pelton's stat, IDK),
It's not.
which I always have hated, even more so because they refuse to give the formula for the stat.
Yes, what's up with that.
Having said that, I don't think that I could evaluate it anyway.
I do trust that the plus/minus module of it, controlling for who else is on the court, has been done accurately.
I don't know how to evaluate how much weight they've given to box score priors, even if I knew what it was or how they've translated them.
I also wish that they'd make their web page sortable in several dimensions, like by team, and let you search by individual player.
Anyway, I find it to be a very useful stat that is looking at the big picture; that's absolutely essential, and I don't know a better place to get what it gives you.