Objectively what you've written is "true", but if you even scratch the surface it's clearly not realistic. Yes, "anyone" can "just pick up a bike" and "start riding off road", but that actually still relies on a few key assumptions, and also doesn't accurately describe what really any of us would consider to be the world of MTB that we seek to share.
The barrier for entry is not supremely low at all; it requires access to expensive equipment, access (and transport) to bushland, ideally access to actual trails etc. If you want to race, that only increases exponentially. Like it or not, one of the key requirements of riding MTB for the majority of the population is a
car. MTBs are also much more expensive than a pair of basketball shoes or football boots or a tennis racquet, so no it's not "pretty cheap" unless you compare it to other sports that have their own diversity and access issues like sailing or equestrian or motor racing.
On the thread generally...
MTB culture has been a massive bro-down basically since forever. The heroes of the sport are people like Shaun Palmer and Steve Peat who popularised a scene much more analogous to the Xtreme™ sports world of MX etc than really any other cycling discipline. They literally banned skin suits in DH racing because the Athertons thought they didn't look cool. As other people have noted in this thread, women's representation has absolutely increased and I really think it's done a lot of good to the scene; races these days are almost unrecognisable from the rum'n'coke and public nudity DH races I used to frequent 10 years ago.
That said, as MTB has moved away from the MX culture, it's moved a lot into the "outdoors" world of $400 Patagonia down jackets and backcountry adventuring. This is a world that the Black communities in America for whom Eliot's program aims to improve accessibility - communities that are overwhelmingly urbanised and more likely to be poor and/or otherwise disadvantaged - have long been written out of. It's no coincidence that skating and BMX which can literally be done anywhere have much more diverse cohorts.
As much as I hate to give them credit for anything, Specialized has actually made some moves in this space, sponsoring various "bike life" riders in the US and the UK, and starting to recast a lot of their imagery away from just white dudes in Colorado. It's small steps and yes people will make all the same arguments about cynical "virtue signalling" for profit, but you can't be what you can't see.
http://instagr.am/p/CCT8TwzluXz/
