I think it's fair to say only those in a position of factual knowledge and personal experience are qualified to respond to the op!
Will an accurately placed .22lr humanely kill a fox out to 150 yards? Yes, that is objective fact
The real question is can the shooter place said round accurately enough to facilitate a humane fox kill at 150 yards? The answer is subjective based upon quality of shooter, quality of gun, quality of sights, and quality of ammo!
Would I, subjectively, take that shot past 75 yards? Not with my .22lr, no!
Should a novice take that shot at all? No, go do some targ