Why? Because moms want it to be everyone's business when they feed naturally or when they are pumping milk for their young? But what about consent?

If a woman strips down half-naked, I'm allowed to feel uncomfortable unless she is putting a mouth or a machine on her breast? No.

That's not correct. I am allowed to feel uncomfortable about that. My feelings are valid. And this woman needs to think about more than her own clients.

I will not be subjected to indecent, unconsented stripping just because a woman is feeding her kid. That loses business, whether you feel it's okay or not. If it was her home, or a private business, okay. But her coworkers obviously take issue with it, and it's a shared place. So share it. Find a sign that is suitable for everyone.