Simply Ken kojaaee ke yadet be kheyr.
First things first, the neutrality of the Guardian Council is something most ordinary people would agree on, regardless of their affiliation. Diplomatic relations with America is also not as big a deal as it once was, in part due to Obama's presence and also since some of the main conservative figures have openly spoken in favor of it. So this leaves us with the question of election legitimacy.
As Khodam pointed out, according to the methodology
52% of those contacted refused to take part! In an oppressive society like Iran where the "wrong" answer can be quite costly, this refusal rate has a much more significant meaning than it does in the West. If these pollsters understood the society they were attempting to poll, this number would have been a huge red flag for them.
While some of those who refused may simply not have had the time, it's safe to say most of them had other reservations, since a pro-regime individual would surely jump at the chance to offer his views to an international agency when the government is facing its worst crisis ever.
Given that the regime has the strong support of 20% of the masses, it's very likely this poll surveyed a full sample of the pro-regime crowd and less than half of its opponents. In other words, whether it was conducted by "a renowned research group" or a gang of toothless baboons, it's not worth the paper it's written on.
Nice try though.