1. People who are into security to prosecute some immortal struggle between good and evil.
2. People who are into security because of the engineering challenge.
It's the people in group (1) that I tend to have a problem with. Often, for the "good guys" security professionals, engineering facts are just a means to the end of winning the war on the "bad guys". These are the people who tell you your Scala serverside application is insecure because of some recently-released Java applet bug; they're the people who fought against DNS query randomization for a decade because we need to finally release DNSSEC; they're the ones shipping grievously broken cryptography to try to "stop the NSA".
There are jerks in both categories, and competition is a dimension orthogonal to this one, but I find I can handle jerkiness and competition between when I know it's from someone who truly cares about understanding what they're talking about.