It's kind of strange that they support TOR users but having in mind numerous safety issues I would avoid blockchain.info.
It's not strange. It's just them trying to expand their reach when it comes to different levels of usage. It doesn't necessarily have to do with illegal things, but could also be focused on maintaining a private identity.
Centralized services are more and more subject to regulations, which might even result in them handing over user information to the authorities, which is why people might choose to use TOR when using centralized services.
It's obviously not as safe as when you access whatever service through clear net, but these people choose to walk a different path, and if they accept the risks tied to that, then it's their problem if things go wrong.