Meanings of supposed inability in English

Great odds were laid against the blind man, because of his supposed inability to keep the course.

The problem of Britain's relationship with the European Union is not London's supposed inability to influence what happens in Brussels.

He expected some sort of protest at this, maybe a dry stab at his supposed inability to do anything without help.

I had not pressed walking up on Vandy's account, while he had only denied himself that wished-for pleasure in deference to my supposed inability.

Rightwing pundits tend to explain Islamic extremism by the supposed inability of Islam to reform itself, together with Muslims' unwillingness to integrate into wider society.