An Argument for Actualism

I came across an argument from van Inwagen for actualism recently. I was wondering what y'all thought about it. The idea is that to be red, in the most inclusive sense, is to be actually red. To fail to be red actually is to be red in no sense at all. Similarly, to exist in the most inclusive sense is to exist actually. To fail to exist actually is to exist in no sense at all. There is no relevant difference between redness and existence. So actualism.

The claim about redness seems right, but the corresponding claim about existence should offend possibilists. So the challenge is to note the relevant difference, if any, between redness and existence. There are clearly some moves to make here, but I was wondering what sort of move, if any, y'all found most attractive.