In another professional life I worked regularly with a lot of journos. Some remain good friends to this day, but we do have to be tolerant and even indulgent about our differing political views, otherwise we'd not be friends.
I'd guess that 80 to 90 percent of the many dozens I knew (or know) are on the center to far left of the political spectrum.
Again it's interesting that the UPI reporter didn't find a "news hook" while standing inside the best combat field hospital in the world. Because during my time in Iraq, Stars & Stripes ran several stories about the Balad operation, and I always thought those were among the best stories they ever produced (a lot of Stars & Stripes Iraq is warmed-over wire copy).
Your observations are good ones and valuable ones.
I think the big big picture of journalism is the culture and the ownership/management.
I say the culture because I think all institutions have a corporate memory. Congress gets used to a life of privilege. Baseball gets used to spitting in the dugout and adjusting things while in the field. Hockey gets used to stars without a full compelement of teeth. Academia gets used to tweed jackets with patches on the elbows. These traditions gets passed on and replicated and they become very ingrained. Journos get used to leftist diatribes and anti-Americanism. And it's hard to change that in short time - maybe even in a generation.
And also management and ownership plays a huge role. In the final analysis all these newshounds and newsbabes server at the pleasure or lack thereof of the owning corporation. The lefties probabably gravitate to the places that they know they'll be appreciated but even if that weren't the case, one adapts to please the boss. It's an old story. Fred Flinstone had to do so with his boss at the quarry and George Jetson had to kiss Mr. Spacely's ass.
So until the culture changes and the management/ownership changes (which is a bit of a chicken and egg problem itself as the reporterettes at some point grow up to be editors and managers) the leftist machine will self-perpetuate.