Why does John McCain hate earmarks?

Some earmarks like the "Bridge to Nowhere", was a waste of money, but it did create jobs for people. Some earmarks are for good things, like understanding life, as in the 3 million dollar study on "bear" reproduction which McCain brought up as wasteful spending. If I did my math right, you can fund 3,333 of those studies for what we spend in Iraq once a month. Why does McCain want to "veto every spending bill", but spend every dime on tanks and blowing up things? Those earmarks he is so against, create jobs right here in America. Will McCain veto spending bills on alternative fuel too? Saying your going veto everything means you are wearing blinders.