A cull buck on my place is a mature buck who's never been and shows no sign of ever being a trophy size. Every buck like that who use or live on my property are taking up space and consuming resources that otherwise could be supporting more promising animals. So they get culled. I also cull aggressively territorial does who chase away any deer that isn't her offspring.
I worked very hard my entire life so that I could buy a piece of dirt to call my own and hunt it. I invest a lot of time, money, thought, and sweat molding it into a big buck hunting property. My objective is to have an exciting hunt where I always have very high odds of seeing and hopefully tagging a big buck. Yes I love venison and I hunt for meat. But I'm not a single faceted man. I'm complex enough of a human to stack multiple objectives, so my meat hunt comes with a big set of horns to serve as a memento, or what some hunters call a trophy.
If going out & shooting whatever willy nilly deer you want just for the meat is what makes you happy then knock yourself out. Nobody's judging you. But I don't personally find that very fun. What's fun for me is owning the land, working the habitat, monitoring the herd & being familiar with every deer, seeing them grow into trophies, and attempting to harvest one of them. It's a comprehensive effort that I find incredibly rewarding. Part of that process is culling animals that work against my goals, and stupid an idea as that may seem to some, it's an effective tactic. And it's not about genetics. I have only so many acres and it holds only so many deer. Every 120" 5yr old is a preventing a potential trophy. He's got to go. Every troublesome doe keeping guard over a plot or mineral site keeps bucks and/or other doe groups away. She's got to go. It's a never ending uphill battle but I enjoy every minute of it. It's part of the process on my place.
That is what a cull buck(or doe) is, explained in my terms for my purposes. Your property may have a different meaning for the term, but in my experience most everybody who works habitat for deer hunting defines a cull the same way. With bigger properties a cull can plausibly steer genetics. On a small place like mine it merely makes room for a deer that might be more promising. That's it in a nutshell.
