"No one wants this deal" except 48% of the sampling base in that poll. 52% of Americans can and have been wrong before about foreign policy matters.
Polls aren't relevant to determining what the proper course of action is in foreign policy, only to gauge which course of action will be popular or unpopular. I'm sure if you took a poll about whether the United States should be more aggressive (up to and including military action) with Iran, most Americans would also be against that, probably to a higher degree.