Not necessarily in this case but in general I am more on the side of the one being criticized. There are so many issues with marketplaces and communities like Ebay, Yelp, iTunes and so on. Very little oversight combined with the power to destroy whole businesses.

Ratings can sometimes be bought, fake or resulting from the customer being incompetent or just a dick. It is often times very hard to get rid of them.

I myself currently have an issue on a marketplace where someone owes me money, but I do not really know how to handle it, because the resulting bad rating would probably cost me even more. I asked the platform what to do about the possibly bad review and they just said, they won't do anything about it. So I get suing.

Platforms should take measures that ensure reviews are real and fair, publish rules and have a way to clear violations. Especially in Valves case, since we are talking about children here and you want to avoid them getting sued. Even though being hold accountable and having to think about how your actions affect others is probably a valuable lesson.