Just because the poll shows 41% think we should be able to own machine guns, doesn't mean that those same people know that we CAN own machine guns.
It also means 59% think we shouldn't be "allowed" to own machine guns, as if it's not already a constitutional right.
Not necessarily, that 59% could also include those that are “not sure”, “only certain people”, or have “no comment”. Those against could conceivable only be 40% or less.