“The Washington State House Finance Committee made revisions to a proposed income tax after a group of progressive lawmakers said the previous version gave away too much while not doing enough for working families.
“A tax break that would have benefited big businesses has been removed from the latest version of a bill to tax incomes more than $1 million is being advanced by Democratic leaders. A group of 13 progressive lawmakers in the House pushed for those provisions to be stripped.”
It might be a matter of language but “uniform” doesn’t really convey “flat” IMO. I would take it to mean the authority couldn’t say this building or subdivision has a different tax rate than the one next to it if they’re in the same territory. That makes sense if you want to avoid governments using taxes as a way to punish a specific individual or business.