It doesn't necessarily mean that agents are the ones doing the shootings.
SSRI's leave people in a pretty suggestable state, and nearly all of these well publicized non gang related, mass shooters were on them. Coupled with the fact that we KNOW for a fact that the government has run mind control experiments through drug/physical abuse programs in the past (MKULTRA), why shouldn't we assume it's still being done?
A certain banking family spread false news that Napolean won the Battle of Waterloo and crashed the British economy in order to buy up the crashing currency.