Because you're a dirtbag traitor who spent years screwing over our troops, that's why.
And let's not forget the dirtbag John Effing Kerry:
June, 1970 – John Kerry joins Vietnam Veterans Against the War (VVAW), a national veterans group that is part of the Peoples Coalition for Peace and Justice. The PCPJ is a broad coalition of local and national organizations, including the Communist Party, USA, “committed to conducting demonstrations aimed at ending the war in Indochina, and poverty, racism and injustice at home.” The VVAW, CCI and PCPJ all have headquarters at 156 Fifth Avenue in New York City. VVAW Executive Secretary Al Hubbard, a former Black Panther, is also on the coordinating committee of the PCPJ. Hubbard soon appoints Kerry to the VVAW’s Executive Committee, bypassing the normal election process. (Winter Soldier- Free Republic)