quote the full scene in avengers when drax says "why gamora?"
This iconic "Why is Gamora" line is from the movie "Avengers: Infinity War" rather than just "Avengers". Here is the full scene where Drax utters this line:
[The Guardians confront Quill and Iron Man's group in the heat of an argument.]
Drax: Allfathers, let the dark magic flow through me one last...
Mantis: We...we have blood to spare.
Drax: -ime.
Iron Man: You guys are so screwed now!
Drax: Bring it, you... I'll... I'll kill you!
Iron Man: Nice beard, by the way. You have one, too.
Dr. Strange: Well, well...
Quill: You guys don't even know what you just started. You just started a war you don't even understand!
Iron Man: It's not a war, it's like a pretty big skirmish, to be honest.
Quill: Is that sarcasm?
Spider-Man: Sort of.
Iron Man: Who's the Earthling who just brought sarcasm in here?
Dr. Strange: I'll do you one better: who is this guy?
Quill: I can't help it, man. It gets the best of me. It gets the best, it just comes right out - I'm sorry.
Drax: I'll do *you* one better: why is Gamora?
Iron Man: Ok, you're not with Thanos?
Quill: *Seriously*? With Thanos? No! I'm here to kill Thanos. He took my girl. Wait, who are you?
Iron Man: I'll tell you on the way. Come on, we have to coalesce.