The bolded would make sense if the estate tax ever was 100%, or was being proposed at 100%. The average rate paid by estates hit by the tax is around 15-20% even when the marginal rate was 40%.
It shouldn't be a major part of tax reform, in any event. It doesn't raise the kinds of funds needed, nor is it a major way to keep inequality in check. First, the corporate tax needs to return to the point it raises as much or close as the individual income tax. Second, the capital gains tax needs to be treated the same as ordinary income. Third, marginal rates need to go down to zero at the poverty line (with the refundable EITC only applying to half the FICA collected up to the poverty line, leave some "skin in the game"), up a bit above the poverty line, and a new higher rate needs to be introduced at double the top current rate (say 46% on $1,036,802+ single, and on $1,244,102 married filing jointly). Finally I would raise standard deduction 5-10% over its current level, and jettison every other deduction except those dealing with catastrophes.