I've always had a love for the look of colour swatches. There's just something very aesthetically pleasing for me. I also happen to enjoy Kermit the Frog. And while I never thought I'd see the two join forces, I guess anything is possible.
Shortly after I had submitted this (which I think was nearly 2 weeks ago) I saw the other shirt that was in the running (it was a Loves Green shirt, which this isn't).
So yes, entirely coincidental. Great minds think alike I guess.