He went after PUBLIC SECTOR unions, which are an actual threat to government, even FDR thought so.
Did you miss the part where Walker went ahead and signed a right to work law that targeted private sector unions after he promised he wouldn't?
FDR also thought locking up 110,000 Japanese Americans was a nifty idea, Mr. Civil Libertarian.
Public Sector workers need unions for the same reason private sector employees do.
Because asshole will inevitably find their way into Management positions, and they will abuse the hired help given the opportunity.