How does Bayesian voting work in ensemble mthods

ensemble_methods

#1

Hello,

While reading about ensemble models through Bayesian Voting I came across:

What does marginalize away mean in this context?
What does the second highlighted line mean.Is it something like since the dataset is large,there are enough data points to support a particular hypothesis compared to others.Also does the Voting process generate hypotheses itself or is there some other explanation??