the "rule" per sey is that no new trails are allowed to be built without the land managers permission. was gnomer built with the land owner's permission? i'm not 100% sure, but i don't think it was. same fate for lola.
even though i've never ridden it from what i've heard i do agree that it's unfortunate that it's gone for the reasons you mentioned.
Gnomer descent was built by Mark Wood and Matt Preston in 2010-11. Was fun connecting ride from Aftertaste (another fun trail RIP).
Trail from Bridle Path is an old hiking trail. think ive seen it in hiking maps as old as early 2000s