To be honest I don't blame him at all. Its not like he is a United fan since he was young, and its not like he's leaving us for money because apparently we are offering him a similar amount. I think he wants to see how the season will finish, if both teams will win their leagues, and see how the state is in midfield for the two teams. No doubt that he is disappointed he didn't get more opportunities in midfield considering how weak it has been for us, even starting Rafael in there over him once (a disaster that one). Both us and Juve are big clubs, and nobody can deny that SAF is coming to the end of his reign, so I'm sure Pogba would like to know how we will be in the next few years, if we will be in decline or on the rise.
Us as fans obviously will call him a cnut if he leaves, but if you think about it, this is a huge decision in his life and not a simple one. He has to choose between the cities, the general lifestyle, where does he think he will get more opportunities to make an impact, what league suits him better, whose style does he like more. I wouldn't be mad at him at all if he left, completely his choice, he's a young kid with his whole career ahead of him, so obviously he will take time on this decision.
It's not like he was constantly in the press, flirting with Juve or constantly changing his mind, actually I don't think he once said anything on the subject. Its just the press that have gone into overload about this one.