I’m not sure the use of a common algorithm was the most damming part of that. They also pooled otherwise proprietary information and penalized landlords who failed to follow the “recommendations”

You could imagine the exact same scheme without the use of a computer.

I think the common algorithm / the computer were the fig leaf, not the enabler, yes. The point is that they tried to launder obvious cartel practices as a simple computer recommendation system.

I think "cartel" might be the word to look for.