I hate how people constantly move the goalposts when it come to claiming that a certain minority of people aren't "paying their fair share". You know who else doesn't pay taxes on unearned income? The 99%. That's about as fair as it can get.
FICA goes to benefits that overwhelmingly favor the poor compared to the rich, so I don't find that argument compelling either.
Your original claim was that the tax code heavily favored the 1% but so far all you've managed to back that up with is a tax rate on their unearned income being the exact same as it is for the 99%'s unearned income. Hardly convincing.
You have to make enough money for starters in order to have income sources that are unearned, so yes this is favored at people who make money. The very wealthy, the 1%, aren't making this money from earned income, they make it from unearned income.
Further, while it is true that "federal income tax" does not include FICA, FICA is a tax on income and the poorest sod pays FICA tax from the very first dollar of income. So it's kinda misleading to say the bottom 45% won't pay any income (related) tax whatsoever.
You can have a case where those 45% are paying 7.65% of their pittance of income on FICA, with no additional income related tax, where someone wealthy enough who has no earned income is paying 0% federal income tax or capital gains tax or FICA on their unearned investment income. And that's just a small example.