Im pretty sure with labels, managers, agents, contracts etc - bands at Faith No More's level at that point, will get told what shows they are doing and who they are supporting.... They can however do everything they can to get thrown off the tour. They were against that mainstream stuff, so in that logic they did show it with actions..... So it makes the 'im against the mainstream but take advantage of it to further our career' point completely void.
A label can't forcibly take you out of your house and drive you to the gig. Bands at their level at the time say no to tours every day.