Reasons are simple..Mubarak ruled as a dictator for 30 years with an iron fist but he wasn't conservative. Staunch muslims couldn't protest to make the country more Islamic as they feared Mubarak. Thirty years of rule by one person gradually weakened the democratic bent of mind in people. Also, local political parties lost support of the mass.

Muslim Brotherhood is a big political party with its tentacles in neighbouring countries as well. Though conservative, through sheer political force, they managed to win the elections. They have a conservative muslim agenda that Morsi is trying to implement. This agenda is not liked by many liberals who have seen Mubarak's rule.