Because they can't just strike whenever they're slightly upset. Strikes are the weapon you use when the negotiations go nowhere and all other options are off the table. And a strike won't work with people who aren't fully committed to lay down the work to fight for a cause. So you'd vote against a strike when you don't think that the cause is so important that it warrants a strike.

I understand why you're getting down voted, so I'll explain a bit: although union members are able to leverage protest for a variety of reasons, that's usually the last thing anyone wants to do. Negotiations are always the first step so that actors or whomever can still get paid, since while on strike that's not paid labor.

You got money saved to survive for potentially weeks without income? Not everyone does.

Different people have different priorities. Sure, pay and benefits is a factor that just about everyone considers. The difference lies in the weight that factor holds for them compared to other factors such as a genuine enjoyment from their work, wishing to avoid taking from the strike fund, or any other factor that matters to them.

For most people, the consideration works out in favor of a strike. In a large enough population, though, it won't for some people. 95%+ is really good. Let's take it and not alienate those that didn't vote for it. That leads to attrition of the union.

I don’t know why you’re being downvoted for asking a simple question.

Could be a number of things. Some people are begrudgingly in unions. They kind of need to be in the union to get the job, but they might not like the idea of organized labor.

Some people might be tight on cash and might also need their regular wages at the moment.