I can't read French (shoot, scroll down to the English), but I believe he was originally invited to share his thoughts and opinions. So the audience of EPFL cared. Now, EPFL doesn't want to risk giving a platform to, or otherwise being associated with, potentially problematic speech that they do not control. I'm sure he can still be a member of the audience at EPFL, so I don't know that this is shunning, per se.