Again you’re missing the point. Regardless of the situation on the ground today, which I might add has lot do with Zia’s dictatorship, he is not being removed from the history. The Parliament is the supreme national institution, and it has the power to take his title away.
In fact, if it was up to me, I would demote him and all dictators who came to power by force to lowest level of military hierarchy, and t give them dishonorable discharge from military & then retroactively court martial them under uniform code of military justice. That would be a justice for law breakers.
As for Zardari, I don’t like the guy, but he is the elected president of the country. He was voted in by vast majority of the parliamentarians. That is why he has law and legitimacy to stands on, unlike those thugs.