I'm not sure what you mean by failed spectacularly, but if I'm reading you right, then your comment is a good example of a reliable phenomenon: nearly everyone with strong passions on a political topic feels like HN is biased against, and even is suppressing, their position. (In one memorable case, the topic we were accused of suppressing was actually the single-most-discussed topic on HN by a long shot: https://news.ycombinator.com/item?id=23624962. That's how intensely these passions work: even the biggest story gets perceived as censored.)

Let's look at the specific topic you mentioned. HN had plenty of discussions about the lab leak theory, starting in late 2020 and all through 2021. I've listed some below; there were others (and of course many more in 2022 and 2023). Some fell off the front page rather quickly but the biggest ones spent 15, 16, 18 hours on the front page.

Everyone's memory about the pandemic has been retroactively revised by now, but as I recall it, the rehabilitation of the lab leak theory in (semi-)mainstream discourse began when Nicholas Wade published his article in the Bulletin. HN discussed that one thoroughly (https://news.ycombinator.com/item?id=27071432) and there had been several major frontpage threads even before that.

An appeal for an objective, open, transparent debate re: the origin of Covid-19 - https://news.ycombinator.com/item?id=28582290 - Sept 2021 (307 comments)

Scientists who signed Lancet letter about origins of Covid-19, have 2nd thoughts - https://news.ycombinator.com/item?id=27631560 - June 2021 (36 comments)

The lab-leak theory: inside the fight to uncover Covid-19’s origins - https://news.ycombinator.com/item?id=27388587 - June 2021 (1062 comments)

Wuhan lab staff sought hospital care before Covid-19 outbreak disclosed - https://news.ycombinator.com/item?id=27259953 - May 2021 (346 comments)

The origin of Covid: Did people or nature open Pandora’s box? - https://news.ycombinator.com/item?id=27071432 - May 2021 (537 comments)

Scientists who say the lab-leak hypothesis for SARS-CoV-2 shouldn't be ruled out - https://news.ycombinator.com/item?id=26750452 - April 2021 (618 comments)

The WHO-China search for the origins of the coronavirus - https://news.ycombinator.com/item?id=26609494 - March 2021 (209 comments)

Why the Wuhan lab leak theory shouldn't be dismissed - https://news.ycombinator.com/item?id=26540458 - March 2021 (985 comments)

US raises ‘deep concerns’ over WHO report on Covid’s Wuhan origins - https://news.ycombinator.com/item?id=26125145 - Feb 2021 (632 comments)

Ensuring a transparent, thorough investigation of Covid-19’s origin - https://news.ycombinator.com/item?id=25799858 - Jan 2021 (74 comments)

Israeli startup claims Covid-19 likely originated in a lab, willing to bet on it - https://news.ycombinator.com/item?id=25585833 - Dec 2020 (351 comments)

(There of course were many threads arguing the opposite as well - I'm just listing these because they're the relevant ones for answering the GP. If this post makes you feel like HN was too supportive of and/or too suppressive of the opposite side, please re-read the first paragraph - it seems to work the same way in all cases.)