This is spot on, and I'm glad someone pointed this out. I'm not a product manager, but can recognize that when working outside of my field of expertise I could probably use some guidance when it comes to building a product for said field.
So why not take that guidance directly from the users of that product. Sure if that really isn't an option (though it usually is even when people and business make excuses for why it isn't) having a "user representative" is a distant second that must be accepted. However it is still your job to build some level of shared domain knowledge with the users of the software.
