I think you need to step back a little and think about your whole line here to understand why you didn't get any more value. Look at the pre-flop action, you get a UTG open to 3x and a call from UTG+2. What are the hand ranges that are doing that. You have to figure that UTG opening (without any other specific information) is probably something like 77+, AJs+, KQs that sort of stuff and the flat from UTG+2 from my experience is a lot of suited broadways and high suited connectors. That being said you 3bet the something like 2.4x. What is your perceived range with this kind of a move. You are 3betting, but smaller. Looks a lot like KK+, AK there. You want more value, but you don't want to scare everyone off. You pick another caller out of the BB (ATC is possible, but not likely here. My guess is suited connectors, suited one gappers that sort of stuff). Flop comes down J 6 8 with 2 clubs and you lead out for 25% pot into 4 opponents. I think based on your line not many people are going to be calling you here as this flop doesn't really do much for anyones range. Based on your actual holding there aren't really any TP type hands that could have been made out there (very very rare that the last J is out there). The J probably gives the UTG and UTG+2 villains some 3 straights, but that is about it. Factoring in perceived card removal based on your actions and they can't be very confident that they are going to do anything but chop or may not get there because you could be holding the top of the broadway, so no real way the continue there. the 6 and the 8 are cards that can hit the calling range of the BB under normal circumstances, but give all of the action in front, I don't think he is sitting there with 57 or 79 very often. Flush Draws just aren't all that common and with 2 on the board chances are no one has them or will be chasing (or at least very small <5% or so)

That all being said, I think awareness of your own line and perceived range is a huge part of these types of situations. This entire hand your repped a huge hand so the only way you are getting called or played with is by a monster that in all likelyhood has your set of J's crushed. Flatting here given how deep you are and the other stacks in the hand are would be more valuable I think. Your hand would be very well disguised and a lot more people with draws would be inclined to play at least to the turn with you giving you some shot at increased value.