Let's start by getting one thing straight, if you want to put forward an ETHICAL case for killing deer, that will be acceptable to the populous, then deer are either killed because they are recognized as a source of food, be it farmed, or wild, and, or they are killed because they are destroying the crops required to feed the population !
Anything else is just killing for fun, or sport, and rightly, or wrongly, will always be considered unacceptable by the majority !
Then we have technology. Rock to spear, spear to bow, bow to flintlock, flintlock to modern rifle, and it goes on. All been said a million times before, but regardless, all MASSIVE leaps in the ability for man to kill, and provide food more efficiently.
So if you're in the "I kill for fun/sport" camp, I understand why some of you would want to make it harder, and more challenging than it needs to be, but don't then try, and justify using scopes, or binoculars to see deer you wouldn't otherwise see, and tell the rest of us that the use of a TI is "unethical" !
Yes, I use a TI. It has been the best education I have ever had. Most paid "stalking", is in fact sitting in a high seat, and hoping a deer comes along. I've not been taken out, and taught how to "stalk", I've had to try, and learn myself, and to be honest I'm not very good at it. I "thought" I was doing the right things, walking slowly, quietly, glassing often, but I struggled.
I then bought a TI, and WOW, was I in for a shock. Walking to a seat in the dark, seeing just how many deer were actually around in the woods, and when it was light, realizing that whilst I thought I was doing all the right things, in reality, I was doing it all wrong, bumping deer, because I just didn't/couldn't see them, even with my bino's.
The TI slowed me right down, if I spotted a deer, I'd swap to my bino's, and, try to see it, sometimes needing several attempts, because what was visible with the TI, was really difficult through the bino's. Then I tried to get as close as I could to the deer, and started to learn how to "stalk".
TI doesn't stalk, or shoot the deer for you, nor does it identify gender, unless you are so close, you can see anyway. It's just another tool, helping us be more efficient, just like the modern rifle, scope, bino's, & range finder ! If you don't like them, fine, don't use one. If you can't justify the cost, why have a go at those people who can ? But trying to suggest they are unethical, is in my opinion, just misplaced !
So if you're a professional deer controller, you should welcome anything that makes you more efficient, and better able to do your job, and a TI should be considered just another tool to help you achieve that, even if it's something you don't want, or feel the need to use.
For the more experienced part timer, or recreational stalker, it will do the same, and for the novice it will give you an education no book can give you.