When you compare Human existence to the existence of the Transformers, several things should be considered: Humans are much smaller, weaker, and less intelligent Whereas Transformers can live for millions of years, Humans live for less than a century on average. Humans are overall much more primitive compared to Transformers With these in mind, it should be apparent that Humans are unto the Transformers as flies are unto Humans. Flies only live for days, are much smaller, weaker and less intelligent than Humans, etc. Essentially, Humans are like flies to Transformers. So, can you really hold anything against Megatron or Sentinel for being willing to sacrifice Human beings for the sake of their far superior species? I mean, think about it; long after Sam, Mikaela, Carly, Epps, Lennox, and Simmons are dead, Optimus, Bumblebee, and the rest of the Cybertronian bots will still be around. They are like gods. So, why should a god be considered evil for being willing to sacrifice mere insects?