I think it's easier to find such kind of comments on specialized communities, i.e. where users have a common ground. For example, looking for insightful comment

I think it's easier to find such kind of comments on specialized communities, i.e. where users have a common ground. For example, looking for insightful comments on politics and economics, I usually like to follow the discussions on the Mises Institute site - since there is a common ideology to most visitors there (libertarianism), they don't spend time hating each other and disagreeing on basic views, and can contribute with constructive arguments instead.