I'd rather my applications be opinionated about the way I use them. I want a designer to think it through carefully and choose what they think is the best.

If I don't like those design choices then I'd choose a different browser rather than spend time configuring one.

(And obviously people make browsers for people who love custom configuration. Safari is not one of those.)

Well, Safa is somewhat opinionated. What should I do if I like 99.9% of the browser except one small thing that infuriates me a huge amount? It makes sense to offer preferences, especially to turn off certain things like gestures. In this case, the designer hasn't really gone far enough in determining that certain choices they have made can have seriously negative effects.