Pakistanis will like anyone that raises the "Islamic flag." Get a wahabi sheikh or an extremist shia from Qom to preach hate and Pakistanis off the street will flock to their cause.
For the same reasons Iran is unfavourable in the West, Pakistanis favour Iran.
Re. the poll, well it's not a surprise to any Iranian. I don't like "us," why would a Westerners like us? In the sunni world, wahabism is king for now. Shias vote Iran, sunnis are divided between the wahabi camp and the secular West.
Not a surprising poll at all.
Here's how the poll would have been without the Islamic khomaini regime. The West would favour Iran across the board (the same way Pakistanis get aroused when people talk about Islam and the ummah, Westerners get aroused the second we talk about Persian history/culture etc...). All we need to do is put up two posters advertising Persepolis, the most impt pre-historic site between Greece and India, and we have ourselves the Western praise and worship. In the Islamic world however little would change except that we would gain the vote of the secular sunnis. We would still be shia kafirs to the wahabis so nothing would change there.