Except imo, the pycon staff.

This doesn't seem to be known by most of the people raging about it. PyCon organizers talked to the parties involved. They didn't even kick anyone out, let alone post pictures or get either party fired.

Blaming Python for this is really insane

Think you misread.. nobody is blaming Python or PyCon ..

Really? PyCon has done everything right in my opinion. What would you do differently if you were PyCon?

And you can't blame SendGrid for getting backed into a corner. Even without the DOS attack they still would have fired Adria sometime in the next few weeks with good cause.

here here