The odd thing about Shirk is that it only belongs in white, really. It could probably be stretched into blue, with Fog Bank as a sort of precedent. It's definitely not red.

I bled shirk to red to since each mechanic is in a wedge (as a way to represent social discomfort). Putting shirk in red is tricky, though I believe that it can exist either in specific circumstances: either the mechanic plays well with the card, such as this example, or in specific drawback scenarios like Element Evader.

I always though damage redirection could be red, but damage prevention seems like one of the least red things to have around.

I could see e. g. absorb go full Bant and even black to an extent (compare indestructible), but red?

I don't disagree; the card would be more appropriate in green.