I just checked, and it is still possible to determine who has liked/disliked a specific comment or post in 0.17 by running a database query.
It is not something that I personally have a problem with - I suspect this might be a “necessary evil” to prevent double voting. And I would think that this is the default for any site with voting.
An issue was opened for that three days ago:
https://github.com/LemmyNet/lemmy/issues/2678
I don’t think it is possible through the UI at the moment.