I was in DC yesterday and noted:
(1)Holocaust museum: nearly as "severe" as airports...long lines if you arrive at the wrong time
(2)Freer Gallery
(3)Hirshhorn
(4)Fine Arts
For these last 3 they poke around in your bag if you have one--they are just making it look "good".
Ditto for music festivalls and major public buildings. Not sure why you are surprised:
- open carry?
- terrorist attacks on mosques, synagogues, etc.
- track record of secuirity failures since 9/11.