Watch the Saturday Night Live skit featuring Beyonce and a trio of guys who are supposed to be her backup dancers in her "Single Girls" music video. The article that comes up when you click on this post's title discusses how important it is for us to speak up when we feel something is going wrong.
I also observed that Beyonce did speak up and was ignored. That often happens and it can discourage people from voicing a dissenting opinion.
While it is important to keep giving one's opinion, it's also important for us as team members and leaders to listen to a dissenting voice. The minority opinion will at very least help refine and improve an idea for which the group is enthusiastic.
When I'm part of a team, I make a point of listening for the lone voice and asking for their reasons. Simply asking why someone has a different opinion or approach breaks the "group think" and creates space for a new idea. As the leader, I make a point to ask each member what they think, especially those people who haven't been talking.
Some personality types (per Myers-Briggs) sit back, observe, and then come up with their approach or response to what the group has been doing. If no one asks for or creates room for their participation, it can either come too late or not at all.
As a team member, I am responsible for offering my own opinion AND to solicit other people's opinions - even if the leader doesn't seem to want to hear them.