Common varieties of raspberries aren't purple, and I've never heard of raspberry flavor being purple.
So they didn't remove the red to leave blue, because there was never blue in the first place -- they just switched from red to blue, as this lengthy history explains:
https://www.bonappetit.com/entertaining-style/pop-culture/ar...
And it was seen as a benefit because blue stood out more from the other red flavors -- cherry, strawberry, watermelon...
https://en.m.wikipedia.org/wiki/Blue_raspberry_flavor
> Food products labeled as blue raspberry flavor are commonly dyed with a bright blue synthetic food coloring, such as brilliant blue FCF (also called Blue #1) having European food coloring number E133. The blue color was used to differentiate raspberry-flavored foods from cherry-, watermelon-, and strawberry-flavored foods, each of which is typically red. The use of blue dye also partially is due to the FDA's 1976 banning of amaranth-based Red Dye No. 2, which had previously been heavily used in raspberry-flavored products.
- it's usually sold as "blue raspberry", not "raspberry"; so you know that it's nothing natural here
- it's mostly used in soft-drinks or other foods that are ~~nothing~~ anything but natural
So my guess is that nobody was thinking they were buying something made of actual rasperries; they knew that they were buying something 100% artificial like "mango madness" or "knockout fruit punch"
What product has "blue raspberry"?
I can only think of one raspberry product I buy, and it doesn't have any dye, and is deep red colored (from the raspberries)
Blue raspberry is a standard slushie colour the world over, in my experience.
But it tastes nothing like raspberry?
It's not like most ice-cream flavors taste anything like the real thing...
Especially in the US (not Italian artisanal gelato)
I’ve not seen or heard of the idea since then, although this may reflect my own consumer preferences.
And the two original, traditional flavours of Tango Ice Blast are Red (Cherry) and Blue (Raspberry).
In fact, I can't remember ever seeing any other flavours, although according to their website there are others:
Berry Blue Jell-o[0].
There are a bunch of others as well, but that's the first one that came to mind.
[0] https://www.kraftheinz.com/jell-o/products/00043000200407-be...
I guess you're one of today's 10,000: https://xkcd.com/1053/
I feel like you might run into it at a carnival or theme park. It's found in things like candy, Kona ice, extremely artificially flavored drinks, etc. Junk food.