It`s just sure you are winning. I think you were mostly lucky at that hand. Seems just obvious you hold a monster after check-raising two aggressors behind you.
But we just should not discuss only this special situation. Before having no clear information if the flop helped the other players you need to check the flop.
There are still 5 players in the game, (you+4), betting in first position would show to much strength, no matter if you are preflop raiser or not (esp. if you aren`t PF raiser such a "ragged" board seems to help you more than others, even a dumpass won`t interpret your bet as a steal bet or as "staying the aggressor). So, I think you are completely right(you agreed) at that point. Would be the right decision if you like to steal the pot anyway, but 3,4$ is not a lot and there is just no need to steal ;).
Now we need to discuss if the reraise was the right decision.
After the BB bets small (1$ in a 3,4$ pot, tiny) and UTG do not put a really big raise (raise 1,5$ in a 5,4$ pot (just splitting his bet in call and raise)). He is offering the BB great odds of 1:5 and there is still someone acting behind. Does not seem to show that much strength, too (maybe just thinking about BB could be stealing at such a ragged flop, even offering great odds for drawing to flush).
So, now you raise to $7, what means offering odds of 1:2, killing flush draw and straight draws, even destroying draw of overcards anyway after (esp. for the BB) tiny raises of the other aggressors.
Interpretating your raise as Bluff or Semi-Bluff seems to be hard, esp. at NL Cash and furthermore after two aggressors. So there are just two reasons left, why they should call:
a) Just think you bluff
b) They hit there hand, or more obvious holding high Pocket Pairs.
Anything else would be a mistake in their point of view.
But you got the nuts, you should be sure you are winning (we should not talk about losing against straight flush or other poker now) and so you do not want to create mistakes, you want to make them think they are playing for value or giving them the possibility to try a bluff at later stages.
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Just about this special situation, after your raise, All-In move by UTG there was not a lot to do wrong. Just think you should be happy to get paid out that great after playing that unprofitable.
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At the end I need to say that I`m not playing that much NL Cash, mostly SnG or Tournaments.
Just playing it a little slowlier had be great :).
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