>>51523218They are a part of an organisation
Organisations requite uniforms or uniformity, especially in the chaotic pokemon universe. These guys might not fall in line.
If you haven't done anything wrong the police can't arrest you just because you dress a certain way generally.
Lastly reap world members of criminal organisations often are very easy to spot as they dress a certain way, wear certain things or have identifying tattoos. (Think yakuza)
Giovanni is a controlling type who acts like a ruthless businessman, the execs have different uniforms to show their superiority.
