[disposekinetics]

The purpose of taxes is to fund the budget. This feels like back door social engineering.

[supergarfield]

There are other purposes for taxes, the most famous one being Pigovian taxes, which attempt to price negative externalities into a market: https://en.wikipedia.org/wiki/Pigovian_tax.

The inheritance tax is not a Pigovian tax, but its purpose can also be primarily non-budgetary.

[jacobush]

It's front door social engineering. See also tobacco and alcohol.