Is it normal that my neighbors are so vindictive and cowardly?

While I was stretching at 6am a few days ago, my knuckles hit the wall which was an accident. Since then one of the three neighbors living together upstairs has been deliberately dropping their weights above my bed at night. I know it's on purpose because they used to train in another room and only drop them like an asshole once they were done. No one has bothered to face me besides acting all buddy buddy on the way to our cars and then slamming the doors harder than usual when inside. Cowards.