Why are SWAT teams being used as tools of harassment?

The blogger Patterico offers an astounding and horrifying story that reveals just how out of control some Americans can be in pursuit of a political vendetta.

Notions like “SWATing” feel like a dangerous escalation of already excessive expressions of ideological rage; once the genie is out of the bottle, then every extremist who feels the ends justify the means will use the tactic against those they hope to harass (or worse). The options for police are truly grim; must they become skeptical or wary about 911 calls describing violent situations?