There are certain circumstances in which this behavior might have been somewhat justified.
Such as cops involved in an actual firefight. At that point the necessity to protect human life takes precedence, quite rightly, over the formalities of warrants and such.
So you think cops being shot at in the open cannot take cover in a home without first getting a warrant?
If so, I think you’re the idiot.
This is not and should not be required, anymore than a cop must first obtain a warrant before entering a home where a murder is known to be in progress. As in he can see a man strangling a women through a window.