Sunk-cost fallacy with his indoctrination and vested interest in Bitcoin.
Jack, Twitter, having been invested in early by Union Square Ventures, Fred Wilson et al, who also invested in Coinbase, CryptoKitties, Brave Browser, etc; USV believed they need to, or saw an opportunity to, basically create the whole ecosystem infrastructure for facilitating selling shovels during the "coin" rush.
Many years ago before Fred (at AVC.com) removed the Disqus commenting system - USV sold it off, so clearly Fred no longer had a financial reason to keep utilizing it - I would near daily engage in long-form conversation in the comment section with other experienced individuals of various domains and have engaging and mostly intellectual conversation.
Fred had valued that community, stated so many times and that it was invaluable to meeting many of the entrepreneurs he'd end up investing in - and where he regularly engage with comments. As soon as however he/they/USV started drinking the Bitcoin (Ponzi-MLM-like scheme) then there were people with the countering narrative, highly intelligent regular comments, narratives that all Bitcoin fanatics would have to ignore, avoid, dismiss in order to not shatter their ungrounded, uncriticially analyzed beliefs. Around that time Fred started getting eloquently articulated backlash, he heavily stopped engaging with the comments - and obviously avoided those critical and pointing out flaws, pitfalls, or ignored realities of the narrative they were following and propagating; and helping evolve, not to mention funding a lobbyist organization to "educate" politicians about Bitcoin and crypto-"currencies."
The SEC should have immediately attempted to put a hard stop to them - albeit a challenge with its decentralized nature, but they could have limited the layperson from losing $100,000s; I personally know a few relatively unsophisticated and unknowledgeable, gambling type people who lost large sums - and many who lost a few thousand; most I predict don't announce their losses publicly. Rather the SEC seems in bed with the VC-finance industrial complex, and it seems like their friends must have been set to make money not transaction fees - but also they likely were bought into the earlier or lower part of the Ponzi-MLM scheme, and so then they, as a decentralized "community" of "HODLers" could benefit and participate in essentially pump and dumps; at least "HODL" is the mantra, those making and not losing money of course weren't holding - they were selling, but depended in part on the manipulating the community to hold off from selling - so then they themselves could sell higher - but primarily for the price to artificially get higher and higher.
One young fellow I met ~7 years ago in the valley, having entered Bitcoin early, already had returns of over $40 million - to which he bought real estate with. He then used the rent money to continue buying Bitcoin during the troughs - as many people likely did - helping drive the relatively artificial-baseless price back up, making it continue to appear like there was higher demand than in reality. Rinse and repeat - sell high, buy low; transferring wealth weighted from the late adopters to the early adopters - the later adopters being left holding the bag of various weights depending on exactly when they "invested" in the scheme.