16 years since JustinTV was a thing and this very basic safety feature has finally been implemented. at least it happened at some point.
Go to your Creator Dashboard, click on the Settings tab, then click Moderation. Scroll down to Channel Privileges, and the option to turn this setting on will be there.
I highly recommend Twitch streamers turn this feature on. I've had some stalkers in the past who would have been demotivated from continuing their abusive behavior much sooner if this feature had been implemented before now.
Furthermore, be careful with channel point redemptions that involve jokingly timing out or banning chat users. This new feature could potentially interfere with that particular usecase.