I tend to be in the “fuck corporations” camp, but this doesn’t really look like they’re stealing his work. It looks nothing like the original Charlie the Unicorn. The original Charlie was gray, while this creature is white and rainbow. This is just a reference.

As an analogy, Borderlands 2 has a sniper rifle names The Storm, and it has the red flavor text “tut tut, looks like rain”, which is a quote from Winnie the Pooh. I personally wouldn’t call that exploitation. You could try to make an argument, but it’s so minor and indirect that any argument wouldn’t hold any water