Thanks for the replay. In my opinion it doesn't prove that siege towers are OP, but slow and weak. In two cases you fight the big siege tower army with a smaller army which doesn't contain enough melee units. So it's not a big surprise that the siege towers win.
In the end, the siege tower army gets defeated by the usage of a mixed army with some siege weapons and a small number of sword cavalry. Again, this doesn't look like the fact that siege towers are OP.
However, it's remarkable that in this match a big army of Alexandre flees from the siege towers. At the other hand the siege tower army was also big. It might have been the right decision to retreat, but maybe he could have won if he would have commited his spearmen to bring the siege towers down.