That's only true in relative terms. In reality tax rates go up or down on everyone at the same time, because that's how the negotiations shake out.
If taxes go up on everyone, the rich are still the ones that manipulate the government, but now they have control over more tax revenue. If taxes go down for everyone, the rich are still the ones that can manipulate the government, but now the government has less revenue and can't cause as much damage.
> In reality tax rates go up or down on everyone at the same time, because that's how the negotiations shake out.
This is absolutely false, especially in the US. Progressive tax brackets, breaks for the rich, and targeted changes for capital vs. income, deductions, etc. are the norm. Tax rate change is _always_ selective.