Helpfulnes of reviews: Why does Amazon or Steam not show the number of unhelpful ratings of a review? [on hold]

From my own experience I found the ratio between helpful and unhelpful reviews to be hugely important to assess how much I could trust / consider a review. I noticed that Amazon and also the Steam Store removed this ratio some time in the last 12 months after using it for years. Instead they only show the "helpful" number. You can still vote "unhelpful" and as a user I would expect that my feedback does something but in the current system it is not shown anywhere.

For a project I might need to implement something similar so I am trying to understand why they changed a system that worked for years.

A Google Search does not offer an official statement from Amazon or Steam why they changed this. I found forum discussions where users made assumptions but noone seems to be certain. From the Steam blog (text search: "Taking a closer look") I found out they might have done this in order to combat review manipulation. But this reasoning refers to how they order and filter relevant reviews. Not how they show information about a review.

Do you have sources / insights that explains why they changed this?