I think you have to do that manually for each tweet. The setting isn't persistent.
Anyway, you can also make your account protected, so that nobody can see or reply to your tweets unless you approve. However, I would say it's not fair to claim that "you are using Twitter incorrectly" if you don't make your account protected, or if you don't restrict replies to every tweet you write.
Even if you restrict replies, people can still quote-tweet dunk on you.
What's the point of a "social network" if you use all the most "antisocial" settings?
How do you even acquire an online social network unless you use Twitter "incorrectly" according to the OP?
> How can someone quote tweet dunk you if your tweets are private?
They can't. Taking your account private was supposed to be the reductio ad absurdum conclusion of using Twitter "correctly". I mean that if your account is still public, but you restrict replies, people can still QT.
