There were a lot of things that Shinso is willing to do for the Uchiha clan, he was told recently that in order to better serve the Uchiha clan, it's best if he were to become stronger himself and the only way to do that is doing actual missions. It's not that Shinso isn't willing to improve himself but it's more so the nature of the missions themselves, dog walking? picking off weed? they made the journey towards becoming a great ninja sound so glorious, yet when you actually see the missions for themselves, it's a completely different case. The only reason he's giving it a go is because he's hoping the mission is harder then it lets on, and it's not as straightforward as it depicts, and that's to wipe off the paint from the Hokage's face.
That's one reason why he's indulging this mission, Shinso sees Kazuya to be a powerful figure of the Uchiha clan and for someone to shatter his image on the Hokage rock? he found it completely disrespectful, as if they were spitting in the face of the Uchiha clan. If he knew who the culprits were, he would not let them get away so easily but for now, he's only focused on one task and that's to wash the rock. He is apparently assigned with a partner for this mission as well, Shinso is already awaiting at the bottom of the Hokage rock, waiting for whoever he's assigned with to show up.
That's one reason why he's indulging this mission, Shinso sees Kazuya to be a powerful figure of the Uchiha clan and for someone to shatter his image on the Hokage rock? he found it completely disrespectful, as if they were spitting in the face of the Uchiha clan. If he knew who the culprits were, he would not let them get away so easily but for now, he's only focused on one task and that's to wash the rock. He is apparently assigned with a partner for this mission as well, Shinso is already awaiting at the bottom of the Hokage rock, waiting for whoever he's assigned with to show up.