I would check raise flop for a few reasons.

1. Only 4 hands, but villain has been active.  They have opened up the action pre-flop so we can expect a c-bet on a fairly wet board.  Your hand is fairly concealed so a check-raise could be perceived as 66xx, QQxx, KKxx, maybe KQxx, flush draws, wraps.

2. You flopped top set but have little backdoor equity (2nd nut flush re-draw, 2nd nut straight re-draw), I'd say get as much money in as you can now, and you can get more in with a check-raise than donk bet.

3. Because you are check raising I think your hand is more perceived as a flush draw/wrap, so you may encourage action from smaller sets and two pair combos.

With a hand like KQ or 66, I would like this line against many villains, but with KK specifically, I think it's a mistake because you risk leaving money on the table against another made hand on the flop (imagine he has QQ and the turn comes Jc, you may leave him a stack).

At some point I used to think similarly.  That is, when I x/r my sets and top two, I will be left with a dry top set or top two on lots of turn cards and there isn't much I can do.  Surely, if you flop x/r range is narrowly defined as good made hands, you can quickly find yourself in trouble.  

However, I think the correct way to resolve this would be adding other types of hands into your x/r range, instead of not x/r'ing sets at all.  If your x/r range consists good made hands as well as good draws (NFD, wraps, etc.) you can play well on a lot of turn cards after x/r, and in some sense, your made hands and draws will protect each other in lots of spots.

That said, KK on this flop is a very clear x/r.  Like Tom said, we risk losing so much value (sometimes the whole stack) by just flatting.  Think about this: how many turn cards still leave you with the nuts?  

A major problem with not xr'ing top set when OOP is that villain is often not going to have a strong enough made hand on blanks to keep barreling.  Meaning he's often going to xback draws and see free rivers.  And the hands that are strong enough to fire a second barrel are almost never folding to your flop raise.

IP  there is more of an argument for calling top set to raise blank turns as you can always make sure at least one bet goes in on the turn.  OOP I think you need to fast play your top sets and protect your range with lower sets as villain will often fire top pair or two pair hands again on the turn.

As a pfr OOP I use similar reasoning for cbetting top set of medium or very wet boards, and xr'ing bottom set.  The import thing to think about is what worse value hands villain can bet when checked too.  If there aren't a lot then you need to focus on charging draws and protecting your hand with a raise.

yeah i see what you mean guys and totaly agree. BUT how does a K72r flop changes things?when he is folding 95% of the time when c/raised?is this still the best play

Yeah on a super dry flop with no draws you're much more incentivized to xc and allow villain to pick up some equity so he can barrel turn and we can xr and get more money in with the nuts. But that flop and the flop in OP are very very different.  Just make sure you're stopping to consider how villains range interacts with the board texture before making a flop action.  In general wet boards that hit frequently played ranges call for fast playing of vulnerable nut hands and larger bet sizes.  Dry boards that miss lots of ranges allow for slow plays of nut hands and smaller bet sizes.