THis thread has gone from interesting, to frustrating, to absolutely ridiculous...
There are certain situations riding or racing offload where you cannot sit and be even remotely fast,
smooth, or relaxed. There are certain situations on smoothish ground where you can sit comfortably. In very tough terrain combining sitting and standing is critical, especially when it gets "trialsesque." Using your body to control the bike is everything and that means moving, a lot - you cannot do this with your butt stapled to the seat for an entire ride.
Sitting does not necessisarily conserve energy... Particularly in a long race. The more you sit the more your upper body is worked, particularly in rough situations like rooty/rocky trail, or in whooped out sections. It's about using both techniques to ride faster, smoother, and more efficiently. This is not about being in one camp or the other - utter nonsense.
We ride both trials bikes and the big bikes, and on some very rough and nasty ground with tough climbs and very technical sections, there are situations on the Ktm where I am up and down like a yo yo depending on what I am trying to do, and how fast I am trying to do it. In either case using the bike and terrain to ease the effort with bumps helping me stand and save my legs for example. In the HS races I am probably standing 90% of the time, sitting in some bermed corners that are smooth when I can or in straight sections of which there are few in our series. Difficult to clear large logs, basket ball sized rocky stream beds, and root balls with any grace, speed, or efficiency while sitting.... Imagine?
I see some of the HS videos posted on here and in terrain that is that friendly looking, open, and soft, I would probably sit a bit more too, but in rough terrain at speed it is just not an option. We race on occasion with a top five EnduroX and GNCC guy - super fast and smooth, and I can tell you he stands most of the time and sits when he can or when it makes sense to get through a corner faster. Given the rate of knots he passes me at, I think Im happy to emulate him.
For all you preaching sitting more than standing, buy a trials bike and learn to ride it well. Then go ride some really rough stuff on the big bike, you will be in for a very pleasant surprise.
For all you preaching standing 100% of the time, ride faster, attack corners and tough climbs, you will see there are moments when sitting works beautifully.
Just my humble opinion of course.