The Bush's are a 'Political Institution' Family - they are one of the building blocks of the Washington Establishment in Washington. If anything they at least recognize that Hillary is 'old school', one of the 'old guard' of Career Politicians, a player in the 'Good ol' boy' Club, a group that has elevated themselves above both the Constitution and Rule of Law / laws they pass for OTHERS to Obey. It's a 'Fraternity'. He probably recognizes Trump is not from that 'world' and is a threat to it. He probably thinks this US Citizen 'rebellion' / 'insurrection' needs to be put down so the staus quo of political RULE - not representation - must continue.