The purpose of question bans is not to punish people; it's to defend the site from large quantities of low-quality content.
This is not an argument one way or the other about whether or not this recently implemented system here on Ask Ubuntu is correct. But I think there may be some confusion surrounding it.
It's not about what the people who are banned deserve. If someone is blocked from posting questions, it does not reflect a belief that they don't deserve to post questions. It does reflect a belief that we are not obligated to accept questions from them, but it's not about punishing them. It's about keeping the site working for everyone else. Whether or not the system is justified depends principally on whether it's necessary and effective at achieving that.
You have to post many downvoted, closed, and/or deleted posts to be question-banned. Stack Exchange employees don't tell us how many, but it's easy to see that plenty of users have many downvoted posts and are still able to post. It's not even bad to have downvoted, closed, or deleted posts. An unusually extreme amount of them is what leads to a ban.
I'm not aware of any evidence of users who just had a few "bad" posts being question- or answer-banned on any Stack Exchange site. And there are many people with many low-quality posts that are not banned. If the question and answer bans are something people commonly experience, that would be a serious bug, which should be reported. But fortunately I don't think that is happening.
I think we were doing fine before question bans were instituted, and I'm not sure they're necessary here. Even if they're not, I don't think they're a big problem either. But either way, question bans are a minor part of the way the site works.
I believe no single post can, by itself, ever under any circumstances cause a ban (even if it were downvoted hundreds of times, closed, and self-deleted).
Finally, I understand your concerns may not be personal, but in case they are: From looking at your posts, I would be very surprised if you were question-banned, or anywhere near being question-banned. You have a number of quality posts; a user with quality posts is far less likely to be question-banned even if they also have really bad posts.
Of course, not being a moderator, I cannot view a list of another user's deleted posts. But unless you have many deleted posts, I wouldn't worry, personally. Of course that doesn't mean you have to agree with the policy in general.