DST setting in La Crosse Technology atomic clock

The clock has a confusing setting: "DST?  on/off".  Documentation does not explain it.

The setting directs the clock to follow or ignore the DST signal present in the WWVB radio broadcast. Even with DST "on", it sets to the correct non-DST time when it is standard (winter) time.  People in Arizona should choose "off"; everyone else should choose "on".  Unless you move to or from Arizona, you don't need to adjust the setting.

Until I did research, I did not know the WWVB radio broadcast included information about Daylight Saving Time.  Until I did research, I assumed incorrectly that the user has to manually toggle the DST setting on the clock twice a year, according to the political whims of Congress and local governments who choose the start and end dates of DST.