I guess that stealing Bitcoin is illegal because if they do not belong to you then it is still considered stealing even if people think that Bitcoin is illegal as well.
So yes stealing Bitcoin is still not legal but there is not much that can be done if it happens.
Stealing bitcoin is illegal and a crime. In myc country it is categorized as cyber crime and cyber crime penalty is 1 degree higher. Meaning if the typical penalty for a crime is 1 month of imprisonment, it will be a year imprisonment. Much weight on the cyber crime penalty.