First, I disagree with the definition of "Potluck." As I understand it, potluck means if you show up for dinner, you'll get whatever I have and can rustle up for dinner. E.g. the luck of what's in the pot.
However, Dish to Pass means that everyone brings something to share. I believe that this was labeled "tacky" is because it is perhaps not the best manners to ask your guests to provide for your event. The person inviting is NOT the host, he/she is, rather, the organizer. A host provides everything for entertaining.
I realize that this has become the norm, but that does not make it right. If I invite people for dinner, I provide everything. I always thought doing this kind of thing at work or church was Ok.
On another note, years ago, after a "Dish to Pass" at work, one of our employees revealed that he had hepatitis. Everyone - 800 people - was offered gamma globulin injections, and our insurer said "no more." I don't like eating food when I don't know the health/safety habits of the cook.