They can disagree but Islam is perfect in my opinion and a lot of other Muslims opinion.
I have no problems with the claim that Islam is perfect. My question is slightly more subtle - whether or not any one person's understanding of Islam, without direct divine inspiration, is perfect. Presumably we can all agree there are bad Muslims, but can we agree that two pious, respectable, God fearing people might study the same texts, think about the same religion and come to two different answers without one of them, necessarily, being a hypocrit or a sham or a bad Muslim?
]I'm sorry I do not see what you are getting at...could you care to expand please...:?
The question is whether you accept that the Muslim community's view and interpretation of Islam can change in various minor ways over time. To take another example, there was a long period between the death of Ali and the modern period where Islam was used by some Muslims to justify the oppression of women. That was seen as Islamic. I assume that you do not think that was Islamic and recognise that Islam liberates women? Do you agree that the community's views can change in various ways over time?