The down-voting experiment for LemmyNSFW was disabled a few hours ago. I don't know what you can
see but on my end, there are only options to upvote. When it was enabled ( for a day or so ) there was also
no up/down totals. Are the UI's showing different things?
Downvotes were enabled for about a week or so. There's a setting in your user profile to determine whether posts only show the total additive score or the exact up/downvote numbers.