[codetrotter]

> how can you see their comment

Go to your profile and ensure you have showdead set to yes.

> assert they have been shadowbanned

See https://news.ycombinator.com/threads?id=mpolun and check out how many of their comments are showing as dead in combination with the contents of said comments. (The step above about setting showdead to yes might be required before you follow said link in order to actually see the dead comments). Almost every single one of the dead comments is contributing to the conversation. This is indicative of a shadow ban. HN users would not be downvoting the vast majority of these comments I think.