Biased, abridged, faultyShort version of MTB sizing history:
1980s - take road bikes and fit flat bars to 150mm stems
1990s - add boing but still be road bike sizing
2000s - heretics start going on about benefits of short stems wide bars (but short stems on short bikes short)
2013 - Mondraker forward geometry, duh
AFG (after Forward Geometry) - long, longer, longest (front centre), dumbass short chainstays
2020s - Lee McCormack: "your bike don't fit"; everybody else: steeper, shorter seat tubes (and longer chainstays)
Incidentally, shorter offset forks (an alternative version of longer chainstays with different side effects).
Not being funny Pete but you've missed a massive part of the 90s and 2000s where the influence of dirt jump and DH came into normal mountain biking.
That's kinda where Lee came in. Before reading the article it may help to realise Lee is older and vertically challenged and still rides that style of mountain biking from the 00's and pumptrack rather than Enduro which everyone in the UK is obsessed about.
Personally I haven't run longer than a 55mm stem on any mtb since about 1992 still ride super slack and super steep head angle bikes (obvz for different purposes) and can't stand riding super long reach bikes or stupidly steep seat angles. They're definitely not for everyone.
Lee does have some very valid points but his opinion is just an option and he's wrong to preach his own preferences on everyone else. And to spout shit about anyone other than himself being on the wrong sized frame.
I'm not sure what you changed. Your whole reply is still pretty firmly based on you and your riding preferences. And in doing so comes across just as preachy as Lee.
ie. Short chainstays although not to your taste definitely have their place on a mountainbike. as do short stems on short bikes. as do less steep seat angles and head angles. etc. etc.
The idea that mountainbikes followed road geometry is somewhat wrong and comes from a weird almost football fan mentality of "we're" better than "them". Of course mtbs and roadbikes are similar, they're both just bikes afterall. But for instance, the long stems of 80s/90s mtbs were fitted to put weight over the front while climbing whereas a longer stem on a roadbike has always been about fit, positioning and in more recent times aero gains, For hardtails or roadbikes the double triangle tube constructed frame design has still not been bettered so that similarity in design simply comes from sound engineering principles. it's also a very easy frame design to allow a builder scope to play with tube lengths and angles and seat tube angle believe it or not still makes most sense to be where it will put the rider in an optimum pedalling position whether that be on an mtb or a roadbike. If you only ever pedal your bike while seated uphill then the steeper seat angles of modern enduro bikes do make a lot of sense. but then you are getting into the realms of building very specialist mtbs for one specific purpose. again not a bad thing. but certainly not optomised for everyone or everyone's riding. And when criticising road geometry, let's not forget, most keen roadies climb and descend way more height than the average keen mtb rider and at considerably faster speeds and spend way more time in the saddle. Again, it's a specialist bike built and designed for a particular purpose. Horses for courses n all that.
In summary, I'm basically just saying we're not all the same so don't get too hung up on what YOU* think is RIGHT. If you want to spend your time doing bunnyhops and making vidoes at the pump track a shorter bike is most definitely the best option and it makes sense to tell beginners this but there's no need to be preachy about it. Down the local pumptrack there are kids on cheap hardtails that actually are too big for them who would put Lee to shame making him look like an absolute beginner.
I also came across this article when googling how to work out the best fit for me on a bike. I found the article difficult to understand as it went on a bit. And not quite sure how it helps someone trying to buy a bike, work out what size is best! I am on the cusp of small and medium but have come to the conclusion the only way to know is to try both.