Yes, I agree that this is a concerning trend. Though we have an on-topic page that categorizes such questions as off-topic, there is not a direct link to that help center article on the asking form. Relevant MSE.
Though we put together an on-topic page, the tour page was neglected. People are encouraged to take the tour when they first sign up; for some, it might be the only topicality-related document they read. Just now, I changed the "ask" and "don't ask" bulleted lists away from the default generic stuff to something that summarizes our help center guidelines. Suggestions for improvements are welcome! Hopefully this change will help our problem; if it doesn't, we can consider more conspicuous help text.
In regard to the examples you brought up (thank you for bringing specifics!):
- This question was voluntarily removed by its author after receiving some comments about topicality.
- This seems interesting to me; I think one could argue that it's asking about ways of thinking as opposed to asking for some code.
- This is indeed a question about programming. It is in the Close Votes queue at the moment pending review. As you said, it would be very good to have more people reviewing. There are currently 16 non-moderator users with the close/reopen vote privilege; I encourage all such users to have a look at that queue.