Arkansas

According to their store page, their printer is Bright Blue Ink here in Austin, Texas. BBI is a union shop.

Maybe it's a strategic decision to leave it off in some areas that are more anti-union, though that's just a wild guess. Or maybe they just don't tag stuff as union-made. I'm sure you could contact them (link below) and find out.

https://store.arkdems.org/

https://www.brightblue.ink/

As an aside, BBI has been completely overwhelmed with orders and there have been a lot of complaints about waiting weeks or months for gear. That could be a good thing - maybe demand is significantly higher than they expected, though it's a bummer for people waiting for their stuff.