Without hunting more deer will get hit. That is a far less humane way to die. Dead deer carcasses attract more animals which will lead to more animals being hit.
If we take the absolute position to reduce all harm, the path would likely lead to the spay and neuter of all wild animals until there are no left to cry over.
Nope. I also don't hunt nor did it ever occur to me to control the deer population by intentionally hitting them with my car. I'm sure there are people who have intentionally hit deer but unlikely with any sort of population control mindset.
The fun part is I totally understand why this seems like a logical connection for you but I would be banned for saying it and you wouldn't believe me anyway.
Actually, you're going to be banned for using a vegan community to defend animal murder for sport and then pretending that it's because you give an inkling of a shit about ecology (although even taking that at face value, what you're arguing for is already beyond entitled as fuck, namely you expect to build roads through their habitat and then kill them en masse so they don't disturb you on your drive).
Your existing stupid shit can stay, though, because it's comically representative of how down bad hunters are to go killing animals and create ad hoc justifications for it.