Re: Optimus Prime's characterization (Spoilers)
The only time I felt OP was being brutal(not too brutal, I think OP's actions have been appropriate in all 3 movies. It's his dialogue that sounded like the Terminator lol) was when he fought Megatron, Blackout, and Starscream in RotF right before he died.
Once you get over the need to prove people wrong and "correct" opinions you disagree with, the internet becomes a much more pleasant and less frustrating place. Besides, what's better than letting a silly comment linger on for all eternity so more people can get a good chuckle?