What? That’s fake Tekhelet!

It depends on how the Gemara is learned about the role of the Chilazon. The Radzyners don’t consider the Chilazon to necessarily “source” the color blue, just that the “blood” of the Chilazon is added to the mixture for reasons only Chazal can fathom, which render it kosher based on the Radzyner understanding, and based on that, any blue can be added to this mixture as long as this ink is in it. It’s a very different way of understanding a text that’s decidedly vague. This is a much deeper discussion which will BE”H be covered in a longer post in the future.