Have you ever had someone try to take the credit for some remarkably good difficult thing you did? Kind of gets you doesn’t it. It’s so brazen you don’t know whether to be angry or just shocked that someone would be brazen enough to do such a dishonorable thing. Then maybe throw in more dirt by exclaiming, “You didn’t build that!”
In fact, most of us try to give some of the credit to others who helped achieve whatever good thing it was. Usually there are others lending a hand at a time it was needed. It’s nice to remember them and point out how grateful you are for their assistance.
It’s bad enough when someone falsely and brazenly claims credit for what others have done. It’s even worse if the person now claiming credit was in fact an impediment to the success of the project for which he’s now claiming credit. It takes a malignant narcissist to insist on the credit for something he tried to sabotage.
That sort of thing will make your hair hurt. We have a shining example of exactly that.