Is quoting really that tough?

Not only is enforced top posting atrocious, but what century do we live in where people on mailing lists -- technical mailing lists! -- still do this?
Reply below with FOO>

This is some text that I'm replying to. It's great and full of wisdom.

FOO> No it's not. Anyone can see that your words are FOO> completely derivative of earlier postings from FOO> much more literate people.

I don't even understand how they do it -- don't modern (and even ancient) mail clients make quoting a reply a non-issue?