David Brock (image on left) is the founder (in 2004) of Media Matters for America. He was at one time a right wing journalist (this was during the Clinton era) and then early in the Bush presidency became a left wing journalist.
As an organization, Media Matters is pro gun control. In fact, in 2010, Media Matters took in $600k in contributions specifically earmarked for pro gun control advocacy.
However, it seems that David Brock, has armed guards. Not only that, the armed guards do not seem to be licensed to carry guns (as the organization is in Washington DC where obtaining a license is difficult to impossible).
So it would seem that Mr. Brock is a hypocrite.
One investigation (by hotair) of Media Matter (specifically on gun control) is here.
One Media Matters policy post on gun control is here.
Another (more recent) such post on gun control is here.
Daily Caller's investigation of the armed guards is here.
Daily Caller's followup of that situation is here.