This is not double taxation.
https://www.investopedia.com/terms/d/double_taxation.asp
The federal government charges you x% for its services. The state government charges you y% for its services. The city government charges you z% for its services. The county government charges you a% of some arbitrary "assessed" property value. These are different entities who have the power to tax you.
>Why can the federal government tax money that can only possibly be in my pocket if I've committed tax fraud against my state?
What? This would only be the case if total taxes on your income exceed 100%. And typically, that would then be up to the courts to decide who is the senior creditor that deserves to get paid.
>Now, I have to pay the federal government. Why should I be on the hook to pay taxes on 100K in income, when I truly only earned 95K?
I disagree that you truly earned $95k. You earned $100k.
In theory, it could be problematic if all of your taxes add up to >100% of income, but I think that's more incentive for people to participate in their government and make sure that doesn't happen. But I don't see why a state that mismanages their defined benefit pensions and infrastructure, and hence has high taxes due to shifting costs from 30 years ago to today, should be getting a benefit for it.