Here is the definition of swagger.
to walk or strut with a defiant or insolent air
When I hear people parrot this weirdness it brings to mind a group of players walking in a peculiar way, like John Wayne maybe.
And when I watch this spread like a disease it makes me wonder if people have minds of their own.
I agree with you when you say it's silly, at minimum it's silly.
People who walk around parroting these 'catch phrases' ( I needed something more derogatory than 'catch phrase') they are lucky to only sound silly, to me they sound retarded.
I'm just being honest here.