While the mental image of eating roadkill is also unappetizing to me, I have to admit my reaction here is irrational.
Eating roadkill isn’t much different from eating wild game you hunted — except with roadkill, it was someone else and their car that killed it accidentally, rather you and a gun intentionally.
If you didn't see it die you don't know what it died of. Shooting something healthy and then dressing it while fresh is different from finding windfall after some unknown amount of time.