Why are governments so reluctant to release corroborated, accurate information in the wake of violent attacks when such a move can deflate further violence?

Why are governments so reluctant to release corroborated, accurate information in the wake of violent attacks when such a move can deflate further violence?
An alleged jihadi attack on a military chaplain in Ireland possibly tied to ISIS just shows how prevalent this threat is.
Terrorism analysis demands consistency and accuracy across the board: this entails the need to talk about Jewish terrorism in Israel
Allegations that three teens planned to target a Taylor Swift event for ISIS should surprise no one and serve to show jihadis are still the #1 threat
Authorities need to take more action in the aftermath of violent acts in releasing info to help prevent uniformed and violent reaction
Many naively believe that terrorist groups a la Al Qaeda, ISIS, etc. eventually disappear: the reality is they are long lasting threats to national security and public safety
It is frightening that with all indicators blinking red on a probable jihadi attack in the offing the Canadian government does not understand the threat
While it is always a good strategy to wait for more confirmation when it comes to terrorism, we can make initial assessments based on what we know.
Hindu extremism is a growing problem in India: do we have to have to worry about attacks outside South Asia?
The perception that violence and extremism are the rise and getting worse, especially far right terrorism, may not be accurate.