You are definitely on the wrong side of the derived works line here, and if your articles are not easily identified as yours that is because in my mind that only means the source has been obfuscated enough that I can't easily trace them like you do with the other stuff found on your site, but you're going to have a hard time convincing me they are original now. If you do not have an agreement with the original source of these articles then you are in breach of copyright law. That may be a conscious decision on your part though.

I would definitely support a ban in this case but at the same time I think there is a need for properly accredited translations (good ones, not crappy ones like these where according to one of the authors lots of nuance got lost) of good content found on non English language websites.

Maybe this is something the people behind Hacker News Magazine could look into, they seem to have the right attitude when it comes to re-using content.