Students of the Colorado STEM school shooting stormed out of an "interfaith vigil," saying their trauma was being politicized. USA TODAY

HIGHLANDS RANCH, Colo. – Gun rights advocates posted support on social media Thursday for students who walked out of a gun-control rally in anger and tears over concerns the event inappropriately politicized their grief.

The event Wednesday was primarily billed as a vigil to honor Kendrick Castillo, who was fatally shot in a rampage by two students at the STEM school here. Speakers at the school's packed gymnasium, however, were mostly politicians and advocates pressing Congress for more restrictive gun laws.

After about 30 minutes, hundreds of students from the STEM School stormed out yelling "this is not for us," "political stunt" and "we are people, not a statement."

Outside, the traumatized shooting survivors thrust lighted cellphones into the air and chanted "mental health, mental health," as their hands and voices shook in the cold rain. Angry students pushed and screamed at journalists, demanding to see photos they had taken.

Frustrated, crying and angry, #STEMschool shooting victims hold an impromptu vigil in the rain Wednesday after leaving a gun-control vigil they felt inappropriately politicized their trauma. (They asked that I not photograph their faces close up, and I respected their wishes.)

— Trevor Hughes (@TrevorHughes) May 9, 2019

Interview requests made by a USA TODAY reporter were rebuffed; multiple students said they had agreed not to talk to journalists.

Many students appeared unaware the event was organized by the Brady Campaign to Prevent Gun Violence. Sen. Michael Bennet and Rep. Jason Crow, both Democrats, both spoke at length about the need for federal action. The Brady Campaign invited reporters to cover the event.

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The students drew plenty of support on social media.

"These politicians remind me of ambulance chasers," posted a Utah woman. "Ready to pounce on the next big shooting with their gun control agenda."

A Colorado woman posted: "Love this so much! I’m so proud of these students! After some rough political months here in Colorado this was a welcomed sight & hope for our future!"

In an apology issued afterward, the Brady Campaign said all efforts should be focused on supporting the STEM students, families and faculty members.

"We are deeply sorry any part of this vigil did not provide the support, caring and sense of community we sought to foster and facilitate and which we know is so crucial to communities who suffer the trauma of gun violence," the statement said.

Some STEM students and family members held a private vigil earlier in the day. They said the public and journalists were kept out to permit anguished students and their parents a chance to grieve together away from the media spotlight into which they have unwillingly been thrust.

Kudos to these kids for refusing to be a weaponized talking point while mourning this terrible event. The adults in the figurative room should be ashamed of themselves.

— SandyAndreas (@SandyAndreas5) May 9, 2019

Castillo, 18, was killed and eight students were wounded Tuesday when two teens opened fire in classrooms at the K-12 school specializing in science and math. Castillo, three days away from completing high school, and two classmates charged one of the shooters at his school. The avid hunter and fisherman was killed.

Colorado Gov. Jared Polis signed "red flag" legislation last month providing judges with the power to temporarily remove firearms from people believed to be at high risk of harming themselves or others.