Do you think they have the right to break down your door unannouced for a GOOD reason?
I recall a lot of cop dramas doing the battering ram thing while announcing "POLICE" quite audibly mid-swing. Regardless of the basis in fact, that seems more reasonable than ramming the door and running in like a military operation.
You're right, there's no good reason for unannounced door destruction regardless of the perpetrator. This proves that the government is increasing its scope of power for its own good, in my personal and humble opinion.