I think I might rephrase it so it has less of a "do it NOW" feel. But here's the gist of it.

Uniforms aren't just clothes, they're also symbolic of an organization. For example, a police or military uniform is symbolic of a state or country's power and authority. Wearing that uniform presents you as an agent of that organization, as someone who wields that power and authority. Destroying that uniform is like destroying a national flag; it sends a clear message of how much respect and obedience you have towards the organization it represents. 

For the time being, let's just say that Shade has trust issues :)