The original bitcoin software ran on Windows if I'm not mistaken, so I don't know about "mostly Linux users".
Maybe it was different in the US. In Europe I get the impression the FOSS community is predominantly left-leaning. My local Debian community certainly is, and they're anti-cryptocurrency (like myself).
Slashdot was also quite skewed against bitcoin, and that was a pretty international geek readership.
The first Bitcoin difficulty adjustment happened on Dec 30 2009. Which means that for entirety of year 2009 there was on average just one computer mining Bitcoins.
Not really a stretch. I have a similar story that I can attribute to 2009/2010 (attempting to mine on the person's computer I was living with at the time)