I think there's an understandable pride amongst IFR freight pilots for the working conditions they have to deal with that sometimes carries over into an assumption that the flying makes them "better" pilots. I have no doubt that flying a metro or 1900 single pilot requires a ton of skill, and have a lot of respect for anyone who does it safely and successfully. But it's incorrect to think that the experience makes them inherently better candidates for two-crew 121 or 135 operations. By the time you've gotten enough time (at least now, and formerly at many regionals) to get to an airline or good 135 jet job, you probably have decent instrument skills.
From interviewing at several airlines and with a couple of employers aside from aviation, personality is the most important selection criteria once a baseline experience is met. You can train someone to your standards, but someone with an attitude like
is probably going to be a serious pain in the ass to work with. I suspect I got my upcoming internship over people who did substantially better or more relevant research by simply not being overly weird or cocky in the interview.