You actually make a good point, but I don't buy the idea that if someone does something wrong which is considered the norm in his time, then he should not be held responsible/liable for his actions.
Definitely, he is responsible and should be held liable. The point though is that he is dead. He can't be brought to court, put in jail etc.
What needs to happen is that his infallible status needs to be completely removed INSIDE MUSLIM MINDS.
The clerics won't do it because it serves their interest to keep the myth of Mo as the perfect human being going.
So it's left up to us atheists, secularists, and reformers to try and hold Mo responsible, retroactively, by lowering his status in the eyes of as many Muslims as we can.
There are a lot of wrong things which are culturally deemed appopriate in my culture. Hitting your children is one of them, but i would never hit any child if i had any. Nor would I force my sisters or nieces to wear hijab. Or marry a 15-16 year old girl. All of these are perfectly OK culturally, but my conscience tells me they are wrong, so I don't do them.
All those things, you feel because you live in this day and age, and even though you're in a heavily Muslim country, it is not Saudi Arabia, and also because you are getting exposed to different ways of thinking. Our sense of morality is always evolving (unless religious dogma has us brainwashed to the point that we resist that evolution of thoughts).
If a 20 year old is able to see the wrong in things that are considered perfectly normal in his culture, then why should a 60 year old be exempt from not seeing the wrong in his actions in his culture?
Even in nazi germany people allowed jews to hide in their houses despite it being in the culture to kill them all.
Well, because Mohammed WAS a pedophile. He wanted to have Aisha as his wife. Whether she was 9, 10 or 14 when he had sex with her, it doesn't matter. By today's standards, he was a pedophile.
However, this only goes against him (personally, not against his tribe) as long as he is revered as the perfect human being *for all time* to follow and imitate.
We can't bring Mo back from the past and put him on trial. What we CAN do is break his idolization in popular Muslim culture (and thus in Muslim minds, eventually).