Relatively new AFL fan here. Can I get an ELI5 over the controversy between Port Adelaide and Collingwood over the black and white striped guernseys?

Because I'm an American, I freely admit to being oblivious and unknowing when it comes to my new favorite sport (AFL) and I need a bit of help understanding why clubs would argue like this over colors. I need someone to "fansplain" why Port Adelaide would want to wear Collingwood's colors and uniform. I also need to a bit of help in understanding the flack over seating at the MCG that Collingwood is getting.

I would really like there to be no bias if possible. Just like with NCAA American football, I know there are huge and emotional traditions that are honored in AFL (and should be) and I know that with branding, the logo and uniform are very tightly regulated, so I'm really at a loss as to why there would be any team wanting to wear a team's guernsey. Would someone please explain to me what's going on?

Edit: Thanks very much, y'all. I think I understand the problem with the uniforms. Can someone explain the issue with the seating at the MCG too?