And while happily displaying the sender email publicly, it gives no indication that someone has embedded (potentially malicious) javascript in a post (why that is even allowed is another question), or that some expected 'blog posts' are actually unexpected redirects to external sites that can contain even more malicious/illegal content.

Leaving aside that a site like this is so wide open for abuse of all kinds it won't last five minutes, I don't even see the advantage of submitting a form at an email provider over simply submitting a form directly on the site.