

I just got the idiom
For context, I am a 41 year old American by birth.
Last night I was baking. I made three little cakes out of 1 master yellow cake batter to frost and fill differently for my friend's birthday tea party today.
One of the cakes has lemon frosting and blueberry filling. My housemate was sitting in the kitchen watching his "favorite cooking show" and hanging out with me. I was talking about how the blueberry filling was less runny this time around and he, in his over-the-top "Merica f yeah!" voice said "these colors don't run! Red, white and blueberry." It was just a silly moment.
But it stopped me in my tracks this time.
I've heard the slogan "these colors don't run" a million times at least. But.
*From a fight.* It finally struck me, "These colors don't run (from a fight)." 41 years old. 41 years in the US and I really thought it was just a weird way to declare yourself tough, because the flag stayed sharp looking through the wash. It's a play on colors running in the laundry, but the meaning is a jingoistic slogan about fighting.
Just thought I would share that here, because I feel like anyone else will just be like, "duh, how did you not get it?"
I know jokes have had a big thread, but do you have any experience with common idiomatic speech that struck you with double meaning after years?
Paw print in Sandstone
20 miles south west of Fairplay Colorado. Wondering what animal left it.
Who else is exhausted with the constant reminders?
hE's A gEmInI.