I took a friend down there on his fourth mountain bike ride ever. He laughed and said this trail is nothing more than a glorified sidewalk, let's go back to Burke.
So he forgot to have fun then?
Sometimes easy trails can be fun. I don't find Bobsled challenging, but it does make me happy to ride once in a while.
As for ratings, they are subjective to local area and what we are used to riding locally. If you've travelled at all anywhere outside of BC (and even the US PNW), you know that even our "green" trails (speaking largely of singletrack trails) are significantly harder than elsewhere.
Riding "mecca's" in North America like Bend, Tahoe, Mammoth, Oakridge, etc typically use the same green, blue, black. And what is green is often shockingly easy. We'd call it a multi-use path. Many places, the black diamond rating is more like a local blue minus the gradiant. Many of our black diamond trails that we consider dumbed down would still blow minds of many visitors from less root infested, gradient deprived locales.
So, it's all relative and subjective and who really cares (except the tourist selecting the trail for the first time). It's more what you take out of the trail. I've ridden some mighty fine multi-use pathways in my day….