Trees, mounds, etc. are natural features of the golf course. The architect (or greens committee or Mother Nature) designed them that way. You hit there, you pays your money, you takes your chances.
Divots are anything but. They are man-made artifacts that represent destruction of the course. Players and caddies are expected to replace them, both as courtesy to other players and to aid in healing the course. Grounds crews must repair them. Whether or not the rules recognize it, what else is that besides ground under repair?
Let me take this to the absurd, to make a point that still holds. Suppose 1000 players take divots in the same 5 foot circle. They create a semi-crater. Wouldn't that be declared ground under repair? Seems to me the logic is the same when you hit into one divot.
You rake bunkers after hitting out of them, or even touching them. Why? To make the course equal as possible for all players. As "fair," much as some of you say you hate that word and see in it the destruction of both golf course architecture and the game itself. If you don't rake traps, golfers who play later face a tougher course. In the last 36 holes of a tournament, that means you are punished for playing better.
So what is the difference between repairing "divots" in a trap and divots in the fairway? If anything, sand is more forgiving of its "divots." You usually play an explosion shot anyway.
Patrick -- it's not marking the ball on the green that improves your lie. (Though plenty of golfers cheat there, including I bet some pro's). It's cleaning it. Then of course you get to point the Titleist logo along the line you have chosen ... or if you prefer seeing all white, turning the ball that way. Also, suppose your ball plugs into the green, or stops in someone else's ball mark. You are allowed to repair the ball mark, so you putt on a smooth surface. Same with any ball marks that are on your line.
Bob Huntley -- since you brought up life, golf and fairness, of course they often are not fair. But we owe our wonderful lives in part to people who gave their blood to make things more fair. It's cavalier to say "it's unfair, get used to it." Sit back and take it? Is that how the people on this board approach life? No way. We try to make life better.
Golf tries to keep things fair, too. For each player to face the same course. We can't control weather. But we sure can control divots in the fairway.
We can test the idea to see if it gets abused. If it doesn't work out, drop it.
Doubt that will ever happen, just like I doubt they ever drop offsides in football. (They could try that out easily in some friendlies.) But it is the right thing to do. IMO.