As far as one-downmanship-- it can make sense in personal situations where trust is high and someone opens up about suffering. Perhaps in other high-trust instances, where it's likely to be interpreted as bonding/guidance and not muscle-flexing. But even in those cases it can quickly become unhelpful, hence the Python sketch getting lots of laughs.
In the case of political rhetoric, do you know an example of one-downmanship that isn't mere muscle-flexing? Just look at the example here-- OP said they find it "funny" that a generation of people are frightened by decreasing opportunities and the dangers of climate change.
Perhaps pre-internet this was a way to at least get a dissident message out before one got cut off in a live interview. A kind of "sign of life" to sentient beings in the audience. But on HN-- where those constraints don't exist-- it looks to me like the kind of low-effort disruption on par with asking, "What about Visa/Mastercard monopoly, or the telcos," on the next thread that discusses the Google monopoly case.
Edit: clarification
