I have biked in Yellowstone since 1987 and it has gotten increasingly bike unfriendly - while the administration always bewails the crush of cars. Meanwhile - the NPS has constructed a cloverleaf interchange at Old Faithful so the thousands of onlookers can zoom away as soon as the geyser erupts; there are 40-foot pull-thru parking places at all of the major attractions; 4 people in a car pay $25 - but 4 cyclists pay $12 each or $48.
I have follow park activities carefully- especially cycling related activities. I toured in the park in late July. Never did I see anything related to earlier closure of Craig Pass or alternatives for cyclists - online at the park website, posted at ACA (which would have been a nice thing for the NPS to do), or posted within the park itself.
After 25 years of bike touring, I have to say that the National Park Service is, fundamentally, aimed at automotive visitors with their ever larger RVs and need for auto services. After all, everything is political and car visitors vote - especially retired folks in RVs. Whatever the various superintendents at Yosemite, Grand Canyon, or Glacier say about traffic - they really don't mean it.