Because there are differences in scale and severity. As an analogy, let's say I'm arguing with my neighbor over the loud parties he throw every night. My neighbor counters with the fact that he can hear my dog barking every morning when I take him out for a walk. My neighbor might be correct here. But he isn't engaging in good faith whatsoever -- instead, he's trying to conflate issues of very different scale to purposefully muddle the conversation. This is the problem of "whataboutism" and it's more complicated than just throwing stones in glass houses.
Part of the issue is that it's a problem that only exists in context. If I'm playing golf with my neighbor and he brings up my dog barking first, it's different than if he brings it up as a counterargument to my complaint about his loud parties. e.g. if someone on hacker news is bringing up criticisms of the US (e.g. Guantanamo Bay) in an unrelated topic, there's nothing wrong with that.
Whenever there is discussion of Guantanamo online, Xinjiang is almost never brought up. Here's a few (I promise not cherry picked, they're the first 3 results on google search for "hacker news Guantanamo" with more than a handful of replies) hacker news threads on Guantanamo to show this point: [0], [1], [2]. Not one mention of Chinese war crimes. There are debates over how bad they are, sure, but no whataboutism saying "Guantanamo is bad, but what about X issue in Y country?"
In contrast, there's not a single large thread about the Uyghur concentration camps in Xinjiang on hacker news (or any other major site) that isn't filled with comparisons to the United States of America and its current and historical problems (and thankfully people calling them out for whataboutism). It's a pattern, and it's a real problem, and I won't hesitate to call it out when I see it.
Ok either I've slipped into an alternate reality or you have no idea what a slippery slope argument is, because it literally has nothing to do with any of what you said...
But furthermore, I never claimed that "what we're doing is ok" (it's not, Guantanamo is still bad obviously), rather I claimed that whataboutism is about CONTEXT. Bringing up tangentially related US issues in a debate about greater Chinese war crimes is a bad faith argument specifically because its purpose is to muddle discussion, confuse scale (less than 40 Gauntanamo prisoners vs 1,000,000+ prisoners in Xinjiang). The time and place for an argument makes a difference -- if you're talking about how bad the Germans are for the Holocaust, and I interject by talking about an event where an English Jew was murdered in 1935 by an anti-semite, are you not allowed to criticize me for derailing the conversation? I could say "anti-semitism is wrong at any level" or "the English do bad things to, why won't you acknowledge that", and I would be totally out of line because of the context of the discussion of the holocaust, because comparing some Englishman getting murdered to millions dying in death camps is dishonest.
Part of the issue is that it's a problem that only exists in context. If I'm playing golf with my neighbor and he brings up my dog barking first, it's different than if he brings it up as a counterargument to my complaint about his loud parties. e.g. if someone on hacker news is bringing up criticisms of the US (e.g. Guantanamo Bay) in an unrelated topic, there's nothing wrong with that.
Whenever there is discussion of Guantanamo online, Xinjiang is almost never brought up. Here's a few (I promise not cherry picked, they're the first 3 results on google search for "hacker news Guantanamo" with more than a handful of replies) hacker news threads on Guantanamo to show this point: [0], [1], [2]. Not one mention of Chinese war crimes. There are debates over how bad they are, sure, but no whataboutism saying "Guantanamo is bad, but what about X issue in Y country?"
In contrast, there's not a single large thread about the Uyghur concentration camps in Xinjiang on hacker news (or any other major site) that isn't filled with comparisons to the United States of America and its current and historical problems (and thankfully people calling them out for whataboutism). It's a pattern, and it's a real problem, and I won't hesitate to call it out when I see it.
[0]: https://news.ycombinator.com/item?id=28500597
[1]: https://news.ycombinator.com/item?id=28195746
[2]: https://news.ycombinator.com/item?id=28986757