If someone asks a question and does not look at any comments or answers that come up, how should I treat such people? Also he or she still logged in.
There is no obligation to accept an answer or follow up on comments*.
You can of course comment and ask if the answer helped solve the problem or ask the user in chat if they are active there, for example—but other than that there is nothing to do and users are well within their rights not to accept an answer or respond to comments.
how should I treat such people?
Exactly as you would any other user.
*One of the main reasons for comments is to communicate issues with questions, so the question may be closed if the asker doesn't respond to requests for clarification on an unclear or otherwise off-topic question—but that is a different issue.
Usually you comment because the question is unclear or needs more information. In that case, you could comment to ask for clarification. But if the user doesn't care at all, a downvote and a close vote (or flag if you don't have enough reputation) would do.
If a user receives ends up having quite some downvotes, closed or deleted question, they will be banned for asking more questions.
If the user just ignores you because they think your comment isn't useful, and the post is perfectly okay, there is nothing you can or should do. Just move on.