The activity in the body does not align with the title. Even putting aside whether such activities are justified in this case or acceptable in general, people do not commonly attempt murder or posses explosives at protests.

What the sentencing calls attempted murder, the defendants are describing as one of the protesters watching a police officer preparing to shoot another protester who was running away on their back, and thus shooting in the direction of the would-be cold blood murderer to prevent the assassination attempt. If this description is correct (a big if, but it seems the judge didn't care for examining the evidence), then it's something that wouldn't have happened at all weren't for actions of the officer himself.

As for explosives, the defendants say it was fireworks. Carrying fireworks at protests is common.