WASHINGTON — The lawyer for White House Correspondence Dinner shooting suspect Cole Allen gave an absurd reason for why the CalTech grad should be allowed to walk free pending trial — despite charges that he attempted to assassinate President Trump . Defense attorneys claimed that Allen, 31, was not prepared to carry out a mass shooting in the room where Trump, first lady Melania and most of the top members of the administration were in attendance — because he had a pump-action shotgun. “Mr. Allen has no criminal history — not even prior arrests, which alone would rebut the presumption of detention,” they wrote in an 11-page filing on Thursday. Cole Allen was in a federal court in Washington DC Thursday where his lawyers are fighting for him to be released on bail. Facebook/@Christina Aguayo News “The government’s rhetoric about a ‘mass shooting’ is also unsupported by its own proffered facts. Mr.…