One might say the income tax is an infringment upon all our freedom to interact in the economy as we please. I naturally resent such oppression, even though I'll probably never be in the upper income brakets.
It is very odd that your libertarian impluses are so selective. What have you got against gays? Really they're on the whole just as nice as the rich.. probably nicer.
Certainly it is a grave injustice that Bill Gates has to pay a higher tax rate than the fellow working at McDonalds.. however it is obvious that he is suffering a less irksome state oppression than homosexuals who are utterly barred from what they see as a life of marital bliss. I think your libertiarianism is selective and unprincipled.