Simplistic means treating complex issues and problems as if they were much simpler, that's exactly what Jquery and its suit of plugins (including Amplify) does well.
So 'simplistic' is right? Would 'simplified' be incorrect here?
EDIT: A spot of googling shows that 'simple' is generally held to be the correct word in this context. I guess 'simplified' implies they've taken something complicated and made it simpler, whilst 'simple' implies they've not made anything more complicated than it needs to be.
Pretty sure the author means 'simple' rather than 'simplistic.' It's an important distinction!