"punishment may supress the outward behavior but doesn't fix the underlying root issues causing the behavior"
This argument will work against a yank and cranker, but if you're using it against someone like Ivan's or Ellis' students they're just going to role their eyes very hard and discard the comment immedietly.
The argument fails the instant you consider that it's not mutually exclusive that you use punishment and think about the internal causes behind behavior. This should be an extremely obvious idea if you ponder it for any amount of time. +P is not the only thing done in the field of training where it is on the table to use it.
If all balanced trianing was just +P "with treats thrown in so they feel good about themselves", why do board and trains last 6-12 weeks depending on the issue? All balanced training for behavioral mod would just be a couple private lessons on how to use +P and then sending the dog on their way. Dog araining schools like the TWC academy wouldn't have only 1 module put of 12 be on punishment.
It also needs to be mentioned that the root cause is sometimes not an emotion you want to change. If a dog is fearful and becuase of it becoming reactive as a solution to fear, then you absolutly do want to work on that fear, but sometimes the root emotion is simply misdirected drive. There is nothing wrong with a dog being aroused and wanting to exert drive into the world, but misplaced drive due to lack of fulfillment can lead to a sea of unwanted behaviors. The root emotion here is actually healthy to have, but its unfulfilled.
I won't go into how I believe that punishment and changing a dog's worldview compliment each other extremely effectively. Im just pointing out here that "punishment doesnr fix the root cause" is an argument as tiring as "if human come from monkey, why still monkey exist?"