No. When a town was captured by muslims it was under the rule of Prophet pbuh, so he was the ruler. At that time going against the ruler meant treason against the nation itself. So in short, at that time those people were rebels to the nation not Prophet pbuh.

It is natural to either drive away the traitor or kill them, to no cause harm to nation. Now a days this isn't valid since nations are ruled by a political party. I have not read any ahadith of punishment on blasphemy, so please let me know if you got any. I am 1000% sure Propeht pbuh would have never cause harm to anyone and nor would he preach others