Can otherwise intelligent people also be wrong sometimes?
Yes.
Could the research efforts into a story be insufficient?
Absolutely, see below:
Could they be deceived by a "source" and not verify it before publishing/airing?
Happens all the time. I'd consider that insufficient research, personally.
The other problem I have with arguments like these is that they assume the "mass media" is a coordinated unitary organization with a singular agenda.
Somewhere in the middle lies the truth. The "media" is NOT a homogeneous organization. However, there is most certainly collusion, cooperation and generally accepted "best practices" within the industry.
This is nothing nefarious, mind you. Most people in media are notoriously uncreative, and when someone tries something new, and it works, the rest are quick to copy. Case in point: (almost) everyone on cable news has a Twitter account now. Don't ask me why.
In some cases, a media organization stepping over the line into activism isn't always a bad thing. See the Edward R. Murrow/McCarthy incidents for an example. But that was a different time both in technology and political circumstances...probably not the best example, and shouldn't be read as an endorsement of the Beck/Hannity/Limbaugh tactics of today.
Editorial has always had a place in news, will always have a place in news. My problem with cable media is that "primetime" news is nothing but editorial, no matter which host or channel you prefer. Watch one of those Murrow newscasts sometimes: he read calmly, objectively, stating the facts of the case. When editorializing, he was quick to point out that what followed was opinion, not fact.
This line between editorial and "hard news" has become extremely blurred. This is largely a result of the 24/7/365 news cycle. Opinions don't cost anything to research, and everyone has one. Toss 5 idiots in a room together, and you can easily kill an hour of airtime, without informing anyone of anything. This is TV of the lowest order, and does nothing but reinforce pre-existing opinions.
But the corporate structure of the media has already been well documented, and covered by several great books and documentaries. I'd like to focus on the accusations of government involvement.
I think it is fair to say that commercial television exists for the sole purpose of propagandizing its viewers to purchase certain products and services. That is the essence of advertising; the backbone of television for over 50 years now. So, yes, any ad-supported media is a form of propaganda if you want to cut past a semantics debate.
But- is it
state-sponsored propaganda? For example, FOX News interviewing President Bush is one thing, reading White House press releases without any fact-checking whatsoever is another matter entirely. The military winning "hearts and minds" is understood; the CIA running specific programs, or pushing specific information, is something else.
Does that make sense?