sky_http://forums.tf2maps.net/showpost.php?p=315021&postcount=67
You will have noticed that the map is not part of the update page. This is because it is not officially part of the shipped update. On Novemeber 13th, YM and I found out that the map was cut from the update. The reason given was that Valve felt it was 'too confusing and challenging for new players.'
LOL
Why not just put it in on a beta map server then?
Edit: They think cp_snowplow is confusing (really it being a slightly different/unique attack and defend map) but rd_asteroid wasnt when it first was introduced... comical