Shooting younger bucks are also a result of not knowing what "might" be in the woods. To some, a basket rack 8 is a trophy. No problem, as long as they don't go to killing 10 bucks in a season.
When you go 20 or so years without shooting a buck (intentionally), and still enjoy hunting, waiting for the 140 or so, you can realize how lots of smaller bucks are killed.--How far can people carry on with some patience?
I agree, there does seem to be larger deer being killed.