I'm confused. There are many taxes that only apply to a subset of people. Property taxes only apply to property owners, soda taxes only apply to people buying soda, gas taxes to people buying gas. Tax credits apply to certain people, too, like the EITC or mortgage credits.
What makes this qualitatively different to you?
Also, everyone can vote, so everyone in theory has equal representation. (in practice, the wealthy have a lot more time in their reps' ears than the poor, so they arguably already have a greater representation than your typical voter.)
All the taxes you listed are tied to specific things. A generic wealth tax is saying that no matter how you got your money, there should be a cap on it. It's like locality pay, but on a national scale. I don't know if it's the right idea or not, but it's application is arbitrary enough that it's different than the other taxes.
What makes this qualitatively different to you?
Also, everyone can vote, so everyone in theory has equal representation. (in practice, the wealthy have a lot more time in their reps' ears than the poor, so they arguably already have a greater representation than your typical voter.)