I think the justification would probably be that if they continued listing the item:
It maybe mislead consumers into paying more for the same thing
The reason why people pay more in that scenario is for convenience (IE all games in the same place) but that would be exersizing valves monopoly, so it may be safer to just remove to reduce complaints to steam about the higher pricing because there will be operational cost to processing those support requests and complaints
I don't feel like valve does everything because of lawsuits. Open sourcing proton wasn't due to a lawsuit. Releasing Cs2 as a free upgrade to csgo wasn't due to a lawsuit.
On the other hand and in response to your comment, I think the regulatory fix is that platforms must display their platform fee clearly and separately to the publishers price.
Fyi I like valve but im in no way sworn to them.
I think the justification would probably be that if they continued listing the item:
I don't feel like valve does everything because of lawsuits. Open sourcing proton wasn't due to a lawsuit. Releasing Cs2 as a free upgrade to csgo wasn't due to a lawsuit.
On the other hand and in response to your comment, I think the regulatory fix is that platforms must display their platform fee clearly and separately to the publishers price.