Carnival (incl. HAL and Princess), Royal Caribbean (incl. Celebrity), Norwegian, MSC, and Disney have all currently suspended all sailings. That pretty much covers the mainstream cruise lines in the US.
You do seem to be correct. It was my error. I was looking at available bookings and departure dates for those. I did not see anything on Carnival or Royal Caribbean sites that showed all had been canceled. In response to your post I tried to book a cruise on Carnival,and then RC. It was not until then that you could see most are canceled and future booking dates appear to be pushed out until June.
Good catch.