Curious to know what you think the reason is exactly. Nuclear weapons? Economic imperialism? Ruthlessness?

Indeed I am, and you're right, there is a reason for it. The tech unions don't need to capture mindshare in order to advertise VC-funded startups ;)

We shouldn't assume that YC is hosting this forum out of benevolence. However it is true that this place is also useful for things other than just advertisement, so that's a neat side effect. We just shouldn't assume that that's the primary purpose of HN.

Can you read the non English speaking forums? Because they exist and people post on it but if you're a monolingual American you won't know it.