There's so much wrong here. You seem to have poor understanding of our former players, and their impact, value, attributes, etc. You seem to have poor understanding of the many different attributes that exist, the different types of defensemen that exist, and the ways in which different defensemen utilize different attributes and skills to be effective. But worst of all, you're bashing valuable stats, and you don't even know how they work.
First off, these stats are not "compiled using faulty criteria and entered by people without in depth hockey knowledge". Not only do the people putting these things together have way more hockey knowledge than you, but it's not like they're sitting there manually and subjectively entering every game event anyway. They use official NHL game data, and the models determining shot quality are built on in-depth analysis of the real results of tens of thousands of historical goal events, and hundreds of thousands of historical shot events. And it's not just shot location. It's shot location, distance, type, angle, angle changes, game situation, preceding game events, etc. There are like 15 variables before even getting into the more in-depth adjustments, and they're constantly testing their models for accuracy, and improving them even more.
Most of these obscure scenarios you're naming are either rare enough to not have significant impact on results, even out over time, or don't apply in the first place. It's measuring the quantity and quality of actual shots, so things like Benoit blocking a shot doesn't hurt him in this metric. It's also only 5v5, so things like Benoit not playing PP also do not hurt him. Linemates can impact things, but Benoit is the worst on the team by far, and most things suggest Benoit is dragging others down; not the other way around.
Having a poor xGF% is not an inevitability for a defensive defenseman, and while context is important (just as it is for any stat or subjective evaluation), there is no additional context or data that makes Benoit's results good. Both of our other defensive defensemen have a positive xGF%, and Benoit was positive last year. Yes, he gets more defensive usage (mostly because he's inept offensively), but he's getting secondary defensive usage behind both Tanev and McCabe. He's deployed as a bottom pairing defenseman against easier matchups. Even if we ignore half of the game and isolate only his defense (his supposed strength), it's still bad. He's been the worst on the team by a decent amount in pretty much every defensive metric, and his defensive results over the last 5 games are horrific.