WHY IS THERE STILL POLICE BRUTALITY?

because the world sucks.

Explanation:

These efforts have identified various core issues that contribute to police brutality, including the insular culture of police departments (including the Blue wall of silence), the aggressive defense of police officers and resistance to change in police unions, the broad legal protections granted to police officers.

type of error:

the error in the sentence is a "dangling modifier". a dangling modifier is a phrase, word or clause that "dangles" because there is not target to modify. in this case, "after mopping the floor" is the dangling modifier since it has no word to modify. the noun "house" cannot mop the floor; therefore there is a mistake in the writing of the sentence.