While it seems as if Siri just cannot handle playing playlists on my HomePod (and thanks again to everyone who has made suggestions), I can handoff my playlist from my iPhone to the HomePod. This is better than nothing- defeats the purpose of Siri but it is better than being limited to playing only one song at a time and having to ask for an individual song for HomePod to work.
The primary reason I bought the HomePod was to play my playlists (that I have created from music I bought from iTunes). I am very selective about the music that I like (I do not like current music, streaming music or radio stations- and really only listen to older music). I still buy a few older songs in iTunes once in a while, but happy with the playlists that I have. Before buying the HomePod, I used a Bose speaker and that worked well with my iPhone, Macs, and iPads. While the HomePod can also serve as a speaker in the same way, I was hoping Siri would be able to play the playlists. It just does not seem possible (hopefully future software upgrades will permit Siri to recognize Playlists and names).
I do appreciate all of the suggestions. It appears as if others have had this issue.