There’s a couple of factors here, I doubt I can be unbiased but here’s how I see it. They’re aiming for a trail plan on a Provincial level, with a goal to increase tourism dollars. Obviously there are other health and wellness benefits but the economic factor is the selling point at this level. A secondary goal is to provide support (insurance, funding opportunities) to organizations who want to build trails that fit with their ideals.
The NSTF is hiking-centric, but the ATV(and snowmoblie) lobby is loud enough and spends lots of dollars so they support building a network of multi-use trails for this group, MTB gets lumped in in this multi-use aspect a lot because wheels are involved.
So the plan wants to appeal to the broadest spectrum of people possible. That means you can’t make anything too difficult, gravel sidewalks with noting to trip over so absolutely anyone can enjoy the outdoors. It’s just the reality of planning at this level to benefit the broadest spectrum of the population.
There’s also the continuing agenda of long distance wilderness hiking trails like the IAT or longer loops like Crowbar Lake, Bluff Wilderness Trail, BMBC. To a large degree this means trails on Provincially owned land, in many cases in Wilderness Protected Areas which is legislated to exclude mountain bikes citing environmental damage.
MTB is a fringe activity (really absolutely anyone can walk in the woods without much practice) and the NSTF has a strong belief that mountain bikes have to go on special segregated trails built in a special way to be safe and appease the environmental concerns. At a Provincial level they have to be made for the widest spectrum of users to maximize use. So it’s gravel paths or sanitized trails that beginners can ride that work nicely with Risk Management Plans and insurance policies.
or something like that, maybe @tossedsalad summed it up better