Keep it stock, or make it your own?

I have only been a member of this forum for a little over a year, but I've noticed that there seems to be more "keep it all stock, all original" guys here than in other forums I participate in. (Except for maybe the Corvette forum, there are some seriously fanatical "keep it stock" guys over there.)
I have never owned a vehicle (car, truck, motorcycle, snowmobile) that I did not modify in some way to make it better suited to me or to do what I wanted from it, better. I'm firmly in the "not-stock" group, and I have been my whole life.
I know there are some rare "numbers matching" low production cars that need to be kept as original as possible to maintain value, but collector cars aside, what would some of the reasons be to keep something pretty common all original?
Don't get me wrong, I have no issues with anyone who prefers a 100% stock original vehicle, and I can appreciate the effort it takes to maintain it that way. It just seems strange to me, and I'm trying to understand the appeal, not cause an argument.
I am a dedicated “Your car your way” fella. I like them restored and modified. I modify mine. I have no worries about it because there are more than just a few perfect examples in museums and private hands.

I won’t take a restored vehicle and modify it.
But I will take a beat up POS or poor driver and have my way with it. I say to the resto guys my moto above and “If your that offended by it, you should have bought it and restored it. Speaking of which, if you wanna purchase this car to restore....”