I wouldn't consider PDA as "showing off" or "proving" something. That tends to be the attitude of on-lookers, but (at least for me) not the opinion of the lovers.

For me, I don't "get off" on PDA or specifically make a point to be affectionate in public. My mentality is more along the lines of "I love you and I want to kiss you, I don't care whether there are people around or not."

I just act the same around my lover regardless of what others think. There's no shame in having feelings. I don't believe kissing, cuddling, and hand holding is disgusting and should be hidden from the world.

I had an ex who was really uptight about anti-PDA. I basically wasn't allowed to touch her outside of the house at all. Even if no one was around.

Try doing that for five years. Five years of basically being denied to express your feelings. The relationship basically fizzled, though there wasn't any huge issues.

I dunno. I feel like you can't put "terms and conditions" on love. If you stifle your expression because you don't want others to see you, it's gonna cause strain in the relationship.