This is a rundown of all of the things that the Mountain Biking Illuminati has recently outlawed. Cancel culture MTB, if you will.
Rucksacks
Bumbags only from now on please. In fact, please just bolt/strap/glue any spares directly to your bike.
Short chainstays
Front wheel lifting fun be damned. It’s all about speed plough now.
27.5
Surely you got the memo?
Carbon
Planet killing, mate. Soz.
Air shocks
Far too stictiony and non-linear.
Type 2 fun
We no longer prize anything involving any level of discomfort or element of suffering. It’s about the easy.
24hr racing
Speaking of which, none of this sort of thing.
Being overbiked
We are all now on bikes that only-just stop us from crashing on everything. It’s called Downcountry or something.
Roosting berms
Stop it.
Just riding along
Kinda like how roadies have to call their rides ‘training rides’. We always need to be Progressing The Sport Or Bettering Ourselves.
Not liking e-bikes
We’ll all be on e-bikes by November. It will be The Law.
Being a kid making jumps in the woods
Prepare to have your efforts shamed and criticised by Grown-Ups on social media.
The wrong length socks
No, not those. The other ones are fine.
Climbs on singletrack
All ascending must be executed on fireroad or tarmac.
Mini pumps
Convoluted and over-optimistic CO2 ‘solutions’ only.
Actually baggy shorts
Spray-on FTW. But not Lycra. God no.
Your current bike
It’s an unrideable deathtrap and all of the good times you’ve had on it over the years are now invalid.

Comments please!
Of course, you can actually like whatever the blinking flip you want in mountain biking. This is more of a finger-wag at the finger-waggers.
Feel free to add any more suggestions as to things that you feel have been cancelled within mountain bike culture.