In most science fiction, the bad guys are clearly evil, and anybody who threatens the main characters faces a maelstrom of laser blasts. Sometimes it's easy to fall back on a black and white view of the world, where everything is clearly delineated between good and evil.
The Next Generation was completely different, and showed us that even creatures or civilizations that are dangerous don't automatically deserve to die just because they threaten us. For example, when Picard ran into the Crystalline Entity, he didn't just blow it up right away, despite the fact that it had killed people—he studied it and tried to understand it, seeking a way to respect its right to live while protecting innocent civilians. A Federation scientist ended up destroying it anyway… but at least Picard tried.
An even cooler example is the episode "I, Borg," in which the crew finds an injured Borg drone and tries to bring it back to normal life. The Federation wants Picard to implant it with a computer virus and send it back into the Collective—essentially committing genocide. The Borg have assimilated millions of innocent lives, including Picard himself. If anybody has a right to be pissed off at them, it's Picard. But what does he do? He comes to his senses and refuses the order because the Borg have just as much right to live as the Federation. Just because their society is different and they're enemies, it doesn't justify genocide.
That's a profound lesson, especially today. Unfortunately, the writers totally forgot about it when they made the movie First Contact, but we'll just pretend Picard's out of character rantings don't exist.