Hot tip, if you do have a problem it isn't the strength of your opinions and probably isn't your ability to express them either. Assess the situation to see if one of these 3 things hold:

1) You don't have a lot of experience in the domains in question.

2) The conversation is drifting away from how to reliably make/keep the situation good.

3) Multiple people don't see the things you think are obvious and would benefit from someone stating them - but you're focusing the conversation on things you are uncertain about rather than things you understand well.

Picking a workplace classic, someone really confidently starts advocating that we need to migrate the database from Postgres to NoSQLDb. And who knows? Maybe they're right. If you want the play for an unopinionated person it is to loudly say "wow, this is risky but might have a big payoff!", and get a feel for the boss' appetite for risk. If low, talk up all the problems with NoSQL databases and give him cover to say no, or alternative low-risk strategies to try and fix the problem. If high, start talking about ways to embrace the change while keeping risks low (+ make a friend of the NoSQL guy because you're supporting him).

Bam, everyone is a winner, particularly the dude with no opinion. The trap that was set is trying to take a strong position on something you don't understand. Workplace success comes from making the room better just by being there.