No, it is not acceptable to throw someone's doormat away simply because they are playing their music loudly in the middle of the day. Disagreements over noise levels should be addressed through proper communication and, if necessary, involving local authorities or property management to mediate the situation.
Throwing away someone's property is not only disrespectful but also illegal and can lead to serious consequences, including legal trouble for the person responsible for disposing of the doormat.
If you are experiencing issues with a neighbor's noise, try talking to them politely about the disturbance and finding a compromise that works for both of you. In some areas, there may be noise regulations that dictate acceptable noise levels during certain times of the day, so it's worth familiarizing yourself with local ordinances and laws that can help address noise complaints in a civilized manner.