Within the Egyptian context it would seem reasonable for the Muslim Brotherhood to try and make certain they would have a candidate on the ballot of the Presidential Election, especially given the fact that the Freedom and Justice Party is so dominant in the freshly elected parliament. If anything, the move to ban someone from running on the grounds of a period in jail during the Moubarak period would be considered abnormal and a little bit fishy and undemocratic.
But every country has a different political culture, and different things that are deemed normal. Egypt's transition to democracy will ideally eventually result in a nation with an equally unique political culture and landscape of its own.
Hope that helps
