While Columbia gears up to welcome Ahmadinejad to prove how tolerant they are, ie in typical leftist clap-trap I am superior to you but I am nice so I will let you talk since what you say agrees with what I want to hear, lets remember a bit of recent history.
Back in 2003 a Canadian journalist, Zahra Kazemi, was arrested for being outside one of Iran's most infamous torture prisons - Evin prison. While incarcerated in the prison in question, she died via torture.
To put it more bluntly, the tyrannical regime of Iran murdered a foreign citizen who was a journalist via torture.
And Columbia, which is supposed to be a school of journalism, is going to allow the primary spokesman of the government of Iran to speak on their campus. Columbia is just mad.