But I took the SPLASH post as an enthusiastic Pogo fan wanting to share some fun.
I suspect that was Rick's intention. That doesn't make it appropriate.
Copyright is supposed to stand for something. If it's okay to use copyrighted material without permission in a commercial context (and Splash certainly is a commercial -- as in "doing business" -- context, since it is ad-supported and is used as an attraction to draw people to Comicon.com, with its various commercial aspects) apparently outside reasonable fair use guidelines, then I have trouble seeing what wouldn't be a violation of copyright.