Shaykh Al Uthaymeen said:

If this path is for other then the Muslims is it permissible for a person to relieve oneself in it?

Answer:

No, because the hadeeth with the narration in Muslim “The one who relieves himself in the pathway of the people”

He didn’t restrict it to the Muslims.

The religion of Islam is not a religion of transgression and harm, as long as there is between us and those disbelievers a covenant or protection, then it is not permissible for us to harm them!!

Explanation of Bulughul Maraam 1/411

Translated by Majid Jawed