Sounds like an outdated perspective that should be challenged. Any adult should be free to discuss and share porn in a consensual and adult-only environment, with zero regard for their day job.

Anyone is fine to share porn online.

Just make a spare account and have some shame about it. When it's part of your public persona is when it's a problem.

Unless it's literally of you, then things get a lot more complicated.

Why is it so horrible for a public persona to acknowledge a part of their life that isn't all that extraordinary?

Horrible is the wrong word. It's like meeting someone and they stink.

In my experience the people who consistently fail to draw these lines also tend to end up being some sort of toxic to you and or your friend group and or your company.

Invite a friend who stinks because they don't shower? You're going to lose friends over it who don't want to be around it. Invite a friend who publicly displays porn? Same deal.