system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is collective bargaining and why do people hate Scott Walker?
gpt
Collective bargaining is where legally a group of workers can join together to negotiate or renegotiate their employment with their employer.  Normally you don't have a lot of pressure to make your employer pay you more, if you can get every worker together and threaten to all stop workign if you don't get paid more, you probably will.

Scott Walker thought being able to do this ended up costing the state a lot of money (state employees wanted more pay and negotiated as a group to get it), and he was instrumental in having laws changed to make some of those actions difficult/impossible.  People who benefit from those laws are upset they changed.