He found it in the Pocket of Gordon's coat when Gordon was his captive down in the sewers. He orders one of his men to search his pockets and he finds the papers containing the speech before Gordon can escape.
He intended to read it on the ceremony in Wayne Manor at the beginning of the film. That's also when the senator gets ...
The League of Shadows philosophy can be seen as a form of religion, with Bane being a religious fanatic. As mentioned before the League even excommunicated him prior to the movie for being too extreme, and if an organization that is willing to decimate the population of major cities says something is extreme you know that they are right. So Bane would ...
There is no mention of Bane being expelled because of how he looks. From the script:
Bane was a member of the League of Shadows?
Until he was excommunicated. And a
man considered too extreme for Ra's al Ghul
is not to be trifled with.
So the only thing we have to go on is that his methods were considered too extreme even for the League.
Perhaps they put them in prison with no real evidence?
No, they were properly convicted (it seems).
What the Dent Act did was deny those properly convicted early parole meaning they had to serve their full sentences (sometimes up to 20 years).
What he complain about?
What he is complaining about is that Harvey Dent was a murderer and so "justice"...