The person is talking about being able to see the number of upvotes and downvotes individually on a post/comment, not karma. The latter is already removed. Currently, boost is still showing the sum of upvotes and downvotes.
If you open this post in the browser on desktop, you can hover over the comment scores to see the breakdown. Other apps make this simpler. It's a really nice thing to have now that I'm used to it. I sometimes forget Reddit doesn't have it till I try to check
Feel free to downvote this comment to see it in action
I'm pretty sure this is an instance thing. It's not just karma, it's the ability to see downvoting. So if you don't like the current state of affairs, you need to talk to your instance admins or change instances to one that has downvoting enabled.
Personally, I do not want this feature enabled universally or somehow forced by the app; my instance doesn't have it, and I like it that way. If I don't like something, I can either engage with words or ignore/block/report the person or post. Being able to downvote is lazy engagement, and it doesn't actually do anything beneficial to further the discourse.