If due to a systemic problem, like say the pain of pregnant women being dismissed & minimized, women speak up to address it,do I get to come & talk about my personal positive pregnancy experience, using it as an example of why those speaking to the systemic problem are off point?

My story is valid and I can tell it. I should, even because if anything, it can give hope to those who think pregnancy is a death sentence.
What's problematic is using that story to diminish the systemic problem. Yes, that may not have been the intention, but that's the outcome.

And it's important to be able to clearly delineate issues here. And focus. Acknowledging the great things your partner does is a good thing. Suggesting that this personal experience invalidates the existence of a systemic problem is the problematic take.

Again, that may not have been the intent. And I take responsibility for assigning my own meaning to what was said. It's an opportunity to address an often recurring issue. And I'm taking it. Because I can. You're welcome to disagree and hold a different view.

You might want to research personal exceptionalism. That might help you understand a little better how, specified or implied, a take like that is problematic.
Also, it's something most, if not all people do, myself included. So now that we know better, we can do better.