It can be summarized as "we are all alone" and is based on historical reasons and the "otherness" of the language and the origins of Hungarians.
Not all ethical sluts are polyamorous, and not all people in polyamorous relationships have the "ethical slut" attitude.
The difference between a polyamorist and a swinger is that a polyamorous person has broad-spectrum involvement in their partners' lives, including love.
The red, white, and green flag also is a powerful national symbol.
The national anthem, written in 1823, is symbol of the eastern origins and history of the Hungarians in the form of a prayer that begs God to help the nation.
If it's not canon but fans ship it, see One True Threesome.