As with ALL polls, the only pertinent question is "according to who?".
If you polled the leadership at NBC, ABC, CBS or the DNC you would probably get the result described. If you stop at any local diner across America, not so much. Both liberal and conservative pollsters are guilty of only sampling groups who will tend to tell them what they want to hear, and then utilizing those all-too-predictable results to try and sway everyone else (who they didn't ask) with the overwhelmingly supportive results.
The vast majority of all polls don't mean a thing, and are NOT indicative of true public sentiment. Both sides know this. Unfortunately for them, so do we.