I think it's more than that -- it likely stems from how the IT department is run at a particular company, too. I've dealt with many sysadmins that offer absolutely no transparency into their processes, and in many cases actively obfuscate it. So any attempt to take an interest seems to be interpreted as some sort of threat to their position.

Either way, this is a two-way street. And often times the culture of one group or the other gets in the way. Which is really unfortunate.