The point is very simple - the elections should be fair. The only legal means to enforce that point is the protests. And ignoring the demands of the protesters to hold the fair elections is illegal. Regardless of how good the present party in power is and how much freedom (=to go on Egypt vacation) it allows.
Come to think of it, there's not that much similarity between the Arab Spring and the current protests in Russia. I think the protests are much more like the protests during the recent elections in Iran.