I don't blame you if you think this way. You're canadian. You don't know wtf you're talking about. ;)
1. Not everyone in the US has a job. More than 23 million Americans are unemployed/underemployed.[1] And are therefore paying very little/not paying taxes. A large population means a large pool of tax payers, and an even larger pool of non-tax payers.
2. Income inequality. The middle-class/rich are paying more taxes."CNN: The rich pay majority of U.S. income taxes"[2] The top 10% earners of this country already pays more than 70% of all the income taxes.
3. Entitlements are already killing the US economy. 62% of the federal budget goes to entitlement.[3] Where are you going to get the $4-$6 trillion to pay for Obamacare??? OH RIGHT, 4 straight years of trillion dollar deficit under Obama. The government is already borrowing money to pay for existing entitlements![4]OR tax wealthy people! (those earning more than $250K under Obama's plan).
you are laughably uninformed about the issues regarding entitlements in America.
[1]http://www.cnbc.com/id/49450120
[2]http://money.cnn.com/2013/03/12/news/economy/rich-taxes/inde...
[3]http://www.heritage.org/research/reports/2012/10/federal-spe...
[4]http://en.wikipedia.org/wiki/National_debt_of_the_United_Sta...