Despite the rest of my comment I agree that the thread was poorly considered. It's "hey, this sub has a problem with shitty left wing bad history so lets get conservatives up on their soapboxes. It makes the focus political identity rather than either truth or historical arguments. I started to write up a two different things before scrapping them because the question was clearly priming for "left v right" not "true v false."

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None of that is badhistory, that's just soapboxing.

A huge number of posts on badhistory are both "soapboxing" and critiques of bad history. Whenever you combine history and modern politics you're running the risk of flattening out history to get a containable take away that's "relevant" or distorting the historical claims others are gesturing towards in favor of a political smackdown.

Take this for example

Slavery was OK because Muslims also had slavery [ignoring, for the moment, that you would be unable to actually cite someone saying that in the other thread. Seriously, this is a bad faith claim]

you're taking a contrary position and dramatically flatting it out to create a false dichotomy (either Slavery was AWESOME!!! or there is no legitimate critique of how the history of slavery is presented in pop history). That's dumb.

Bluntly, It is incredibly easy to find people making apologetics for slavery in contexts other than European colonialism (just look at one of the top 5 highest voted all time posts on badhistory). The history of slavery and human bondage more generally (since Slavery is actually multiple very different institutions existing throughout space and time) is much more damning on humanity than can be fully encompassed by a self-critique of the West. You're making a very weird claim that one has to deny Western crimes in order to critique the left for failing to look harshly at examples where the historical oppressor-oppressed axis isn't focused on the crimes of western colonialism or Western abuse of a hegemonic position.

You don't even have to agree with that critique to acknowledge its existence.