Maybe he saw Hunter on TV yesterday...
http://www.politico.com/blogs/jonathanmartin/1207/Tancredo_to_get_out.html#comments
Judging by your link, and one or two posts on the other thread, my guess is that Steve King’s endorsement of Thompson is the opening Tancredo wanted/decided to use to announce his resignation, and then himself openly endorsing Thompson.
It would be interesting to learn exactly what role King has played in this.
Those people commenting are idiots.