Completely disagree with your rationale here.
Take English soccer for instance. You'd never see a team like Sunderland be asked to change its red and white stripes if they were promoted to the Championship because it would clash with Stoke City who too have red and white stripes. What about Chelsea and Everton both wearing royal blue? Birmingham City and Reading both wearing blue and white stripes? Aston Villa and West Ham's kits are identical and yet that doesn't seem to be an issue for anyone. What about Man United and Liverpool who both wear a blocked red kit at home?
In Italy there are zero issues with Juventus (the biggest club in Italy whose brand is the black and white stripes above all else) and Udinese playing in the same bloody league wearing black and white stripes as their primary kit.
This concept is just as applicable to the idea of port wearing the prison bars in the AFL. It's even a looser concept here because the prison bar jumper is a completely different design to Collingwoods black and white striped jumper.
Anywhere else in the world this wouldn't even be thought of or considered to be an issue.
If the AFL had relegation and the best teams from each state moved up each year it would be comparable.