I sympathise with feelings you have Wiggly-Paint about how its used in the wild. I don't want to run to conclusions but there is a possibility that they are just some high-school kid with no bad intention, just very limited understanding of the internet and code. Its very easy to 'accidentally' copy WigglyPaint with a LLM.
Anyway a solution I can think of is to add some sort of backed, which cannot be easily copied. Can be something as simple as drawing storage/sharing.
Hope this helps somewhat!