It's natural, we have a lot of time on our hands (cruising, sitting around in the crew room, bars, ect.), and have to talk about something. Company rumors are the one thing that everyone has in common. Not to mention that company communications is usually poor at the rank and file level. In reality we are usually the last to know. I have read most "company announcements" from press releases. I don't think that this is solely a "commuter pilot" trait. I have a theory that heavy iron drivers are worse, after all they have a lot more time in cruise to speculate/spread/start rumors.
On a side note, it has been my experience that simulator instructors are the worst offenders. I suppose this is for a numbe of reasons; they have access to a large number of pilots, and have the appearance of being "in-the-know".