If you look at the comment sections of actual propaganda sites... well, you won't see Breitbart comments "correct the record". Quite the opposite, they are an important part of the local echo chamber. The only good they can do is giving others an unfiltered view into the minds of those communities.

That is interesting, I wonder if we could use the level of disagreement in the comment sections to detect propaganda vs news sites.

Certainly, but all other things equal without comments there's a reduced opportunity for alternative views to surface on the same page.

Comments do add additional context, it's just a situation by situation basis of whether they are useful. HN comments tend to be useful, YT comments are occasionally useful but mostly garbage.