People who post their own versions of Wigglypaint without lying and stealing art are fine. Change logs for various versions of Wigglypaint actively encourage people to try tinkering with the program. Legit, free and honest modifications of Wigglypaint have always existed, and Internet-Janitor has answered questions helping people make their own modifications in the past
But when we're talking about scams we're talking about people lying about being "The Official Wigglypaint", sometimes pretending to be Internet-Janitor personally and stealing hundreds of people's artworks for their community galleries to look like a legit official website. These scammers are doing shady things to deceive new artists into giving them money, often tricking them into thinking that they're supporting the creator. That's why there's a scam warning here.