Using the X class exclusion code flags the quest as a class quest for all the other classes. It should not do this, I think.
G[792]='K0040 L002 N255 XL A:3145 T:3145' is the one I am thinking of. It's a class specific variant. It does no "harm" to list the other quests as a class specific quest for warlocks. IMO, slightlyconfusing to list this as class specific for all other classes.

But doesn't this mean that warlocks will never get this quest? There is no other way to make that so other than marking it as NOT warlock.

It does mean that warlocks will not get it. But, my point is, that the quest is marked as a class specific quest for all the other classes. It is for the other classes, of course. However, class specific quests are more typically restricted to just that class.
It probably does not matter that much, it just seemed "wrong".

I think you mean that in Wholly the quest appears available for a huge list of classes that can take it instead of the specific "warlock cannot take this". I think that could be handled.

Yes that's exactly what I mean. Thanks in anticipation.