Why are Unions Giving King Cash?

Looking at last quarters FEC filings, the sad thing is he is still getting union money even though he votes against their interests. King has a 37% lifetime voting record with the AFL-CIO.
King got
$1000 from Local 138, 138A and 138B Internationa Union of Operating Engineers, Farmingdale, NY;
$4000 from the International Union of Operating Engineers PAC, Washington DC
$1000 from the Transport Workers Union Political Contribution Committee, NY, NY;
$1000 from the Amalgamated Transit Union - COPE, Washington DC;
$5000 from the Carpenters Legislative Improvement Committee, Washington DC;
$1000 from the International Association of Firefighters PAC, Washington DC;
$6000 from the Service Employees International Union PAC, Washington DC;
$1000 from the Sheet Metal and Air Conditoning Contractors PAC,
$5000 from the Airline Pilots Association PAC, Washington DC;
$1000 from the Transportation Trades Dept. AFL-CIO PAC, Washington DC;
and sadly many more.