The "humans are always evil and selfishness"-type of cynicism is at least as flawed as the "humans are always perfect beings" thinking. Both are wrong. The reality is somewhere in the middle.
Isn't that what I essentially said myself?
The difference is that you're looking at the middle ground and pegging it as "evil." Lorca and Tyler didn't leave behind an innocent but flawed civilian. They left behind a deceitful criminal who betrayed them and the Federation.
There's a difference.
A big one.
Were Adama and Apollo "evil war crime guys" because they left Baltar to die in the Pyramid in Part 2 of "Lost Planet of the Gods?" in BSGTOS? Were you up in arms about the evil, horrible, deplorable behavior on display then? No, Baltar was a dick who sold his people out. Simple.