I remember one time I joined a session and noticed all crews were fighting in the server. Once I manage to take a few of them down who were boarding us, I was able to talk them all into forming an alliance. Miraculously, I ended a server war in the process for the time I was in there. In the process, I also formed server alliance which I didn't think would be because of my words.
My attitude is we all want the same thing (gold, reputation, and renown) and it would be easier if we work together instead of fighting each other hence why I usually advocate alliances. But if my crew unanimously disagrees with me, or the other crew is belligerent/suspicious, I'm not hesitating to defend the ship if necessary, plus a little PvP is actually good for keeping your skills sharp and learning new things along the way.