There is a button on the user perms page which will do all of them:
View attachment 56863
Clicking Not Set (No) will ensure their perms default to the groups they are a member of.
What it doesn't do however is the spin boxes, but I did suggest that the other week.
Once you know what to do it is crazy easy
The problem is figuring it out, the thinking pattern goes like this
"Oh, I see this node has custom permissions"
"no, that is not right, I want to remove them"
Then I search for a delete permissions button (the same way you delete almost anything in XF), but there is nothing, then I click on it and search for an edit or revert, and again nothing
And setting everything to no, seems like "defining" permissions, not "removing" them, and that is not what I have to do, then I keep looking... Then I ask at XF
A rule of thumb for good UI is that you should not need to explain it
Hence, this one is broken