Gargaro is one of several people investigated in recent years for postings that tested the limits in the freewheeling arena of the Web.
"We admit he was stupid," said Jeffrey Lustick, Gargaro's lawyer. But "people say some pretty unusual things on blogs."
Isaac Zamora, 28, began his rampage Sept. 2 near the town of Alger, 70 miles north of Seattle, and continued it on Interstate 5, investigators said. Described by his family as mentally disturbed, he was captured after a police chase and charged with six counts of murder.
The dead included a man who had accused Zamora of trespassing, a woman who lived nearby, two construction workers, a motorist along the highway, and Skagit County Deputy Sheriff Anne Jackson, who had responded to a call to check on Zamora.
The next day, Gargaro began his post on The Bellingham Herald's Web site by telling another commenter to "shut up." He added: "Also to all of you who blame drugs ... shut up as well. You know what, I am going to go shoot up sunset square today ... just for the hell of it. No drugs, no mental illness ... you can blame todays episode on video games and George Bush's example of 'pay back' to society."
An officer in St. Louis saw Gargaro's post the day after the shootings and pointed it out to the Bellingham Police Department. A detective obtained a search warrant and tracked Gargaro down at his home in Blaine, north of Bellingham.
Whatcom County Prosecutor Dave McEachran wrote in charging papers that the detective was "in reasonable fear ... that the threat would be carried out, and people could be killed or injured at the Sunset Square Mall."
But Lustick said his client was clearly trying to make a political point - awkward though it may have been. The comment must be considered within the context of such reader-feedback sections and blogs, which can be "notoriously bombastic," he said.
Noting his client was charged with felony harassment, Lustick also said it was unclear who was supposedly being harassed - the Web site's readers, shoppers at Sunset Square or the detective whose reaction is cited in charging papers.
"There is not one identifiable person in regard to the threat to kill," he said.
The charge carries a maximum sentence of five years in prison, but Gargaro has no prior convictions and would face a standard range of one to three months if found guilty.
The prosecutor did not return calls seeking comment this week. Gargaro, a married father of two, told The Associated Press he doesn't own guns, didn't intend his comment as a threat and was trying to take issue with people who were assigning blame for the shooting before all the facts came out.
"I could have definitely worded it better, but I'm not sorry for what I wrote," he said. "I was just trying to get an open debate going." He is free on $10,000 bond pending trial.
Whether people are charged for making such comments often turns on whether what was said is a true threat, given its context. In December, prosecutors in Wisconsin declined to charge a teacher who sarcastically praised the Columbine High School gunmen in a blog, saying they "knew how to deal with the overpaid teacher union thugs. One shot at a time!"
A month earlier, a man in North Dakota was sentenced to 18 months for posting a comment that the Virginia Tech massacre was funny and including plans for a school shooting rampage in Bismarck.
Stewart Jay, a constitutional law professor at the University of Washington, said it's perfectly reasonable for police to investigate such comments. But, he said, given the tone of the comment and that Gargaro apparently had no intention of following through on what he wrote, that should have been the end of it.
"He's making, if not a political point, a sarcastic point about shifting blame or not taking blame for things," Jay said. "In context, it's just robust political speech."