anyone can post on there

Untrue.

Due to the number of fakes, dumps and non-quality uploads being dumped on 1337x we implemented upload restrictions to protect our users and ensure upload quality.

Users can request trial-uploader status, our moderators will review your application.

1) Before applying please read Upload Rules.
2) In uploader application tell us a brief introduction about you and if you are an existing uploader/encoder.
3) If you are a regular uploader in other sites, state your user name in those sites.
4) State what type of content you are planning to upload and why.
5) If you have accounts at various sites with 25+ torrents contact us via the contact form or in 1337x chat.

This is straight from the upload section on 1337x. You need verification for instant uploading and if you do not you need to get the torrent file verified by the staff team first.