“Right to work” refers to the fact that in those states, unions cannot force membership or payment, or force you to participate in labor strikes. You can still have a union in those states, but it’s very difficult for them to be effective because most people will choose not to pay into it, and strikes have significantly less bargaining power if there’s no legal obligation for union members to follow through with a strike.
The result is that in such states, there are very few unions, and so very few protections against firing workers for arbitrary reasons.
Because you get promoted for changing things, not for keeping things the same. Almost every change like this is motivated by someone trying to get promoted.