The link is to a post a couple weeks after they started I guess.
afaict this was the tweet where they started accepting bitcoin:
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10 sats \ 0 replies \ @Bell_curve 14 Jun
2011 was a big year for bitcoin
Wikileaks
Silk Road
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0 sats \ 0 replies \ @nitter 14 Jun bot
https://xcancel.com/wikileaks/status/80774521350668288
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