This is mostly right but I think missing the point. It’s not 12.2% on the first bracket and 2.2% on the second. It’s 12.4% on the first $184,000 and ZERO On the rest. The 2.2% is not the marginal rate they are currently paying, it is the effective rate if you add up all the the paid divided by all the income. It’s so low because people with salaries beyond 184k stop having to pay any of this tax on their next marginal dollar.

And the reason this is a big deal is because this tax revenue is what is used to fund social security payments for older folks. The social security reserve fund that is running out (which will result in a significant run reduction in payment to these old folks) could possibly be all or mostly funded if we made people making more than $184,000 pay the same rate as everyone else.