You guys are completely neglecting the standard reaction to a cop cruising on the freeway, and how that's different from Joe Schmoe cruising behind you. Most people's primary interaction with a cop is being punished for minor deviations from traffic laws, so everyone in every lane moderates their speed to exactly the limit upon spotting a cop... and you're going to blame the guy for not intentionally speeding up? That reaction should be obvious and routine to any cop who's driven a marked car.
Not to mention the fact that anyone else would've been pulled over for following at an unsafe distance (and that was a clearly unsafe distance). And correct me if I'm wrong here, but the standard conscientious practice for informing someone you want to pass is to flash your headlights at them, NOT to just hang out 18" off their bumper. So pardon me for holding our law enforcement personnel to the same (or elevated) standard of courtesy that the rest of the public is held. Finally, if that cop truly needed to get somewhere to the degree that it warranted unsafe and asshole-ish driving practices, a quick flash of his light bar would have gotten him much quicker results.