Writing slogans does not infringe on his reputation, because you are telling the truth. But the corridor is not your private place. You can't write slogans in the corridor, otherwise the owner can let you clean it up. If you have space to brush the slogan in the owner, the owner can also call the police. The legal way is to wear a coat with a slogan printed on it, or to collect debts downstairs or in front of his office with a sign with a slogan. It is not appropriate to interfere with the normal work and rest of others, or infringe upon the property rights of others, which will cause public outrage.