Don't you think people need to know what they did wrong exactly so they can fix it and get unbanned from asking questions or posting answers?
I went ahead and undeleted your last five or six self-deleted posts. All your deleted questions are almost certainly what caused the ban (because you've asked relatively few questions and a high proportion of them were deleted). None of those questions were downvoted, but try to improve them anyway to see if you can get some upvotes and answers (answer them yourself if you can). In the future, don't just delete old unanswered questions, try and improve them instead. Also, check and see if undeleting these posts alone unbanned you.
Side note: I agree with the reasons we don't tell people exactly what the ban rules are, but I think self-deletion is one case where we should at least warn people that what they're doing is actively harmful. People who are just trying to clean up seem very likely to read such a warning. People who are just trying to game the system by deleting/re-asking are lazy sods who won't read the warning.
The error message you get when you're question banned is:
Oops! Your question couldn't be submitted because:
- Sorry, we are no longer accepting questions from this account. See http://goo.gl/C1Kwu to learn more.
The answer one is similar; both link to What can I do when getting "We are no longer accepting questions/answers from this account"?, which is a pretty massive answer that explains what the user did wrong, how to fix it, and how to avoid it happening in the future
If you're looking for something that specifically says which posts caused it, it's probably the posts picking up downvotes and getting deleted, but (as that page says) the exact algorithm is secret to prevent gaming. If you're looking for something that specifically says why the posts were downvoted/deleted, an automated system can't really do that; hopefully users are leaving comments explaining what's wrong as they downvote