THIS. Seriously, whenever the government started ranting about how the war on Earth was All The Autobots Fault, I really wished someone would point out that really, the humans started it first. Megatron hadn't actually done anything (to the humans) except crash on to Earth and get trapped in the ice. It was Sector Seven that kept him confined for experiments for years, all the while knowing he was a sentient creature. And then they tried to do the same to Bumblebee. Oh yeah, real innocent.

Honestly, if the Autobots hadn't shown up and the 'Cons had found and freed Megatron, I could easily see Megatron razing at least a few cities to the ground, if not the entire planet, simply for the treatment he suffered.