Why should Scott care about what Storm or Captain America would've done in his situation? He's the leader who saved mutantkind from extinction, he doesn't need to think about what the Avengers leader would do, he makes his own decisions, if they wouldn't wipe out the Brood then they'd be wrong and naive, we have already explained to you that they're a race that doesn't deserve to exist, they literally can only reproduce by raping and killing sentient beings.
Also, Scott already wanted to wipe them out before that
And here's what he thinks about the Avengers and their way of doing things