Does a Scrum Master NEED to be technical?

Nope. But it sure does help.

Let's look at this academically, then practically. Please open up your copy of the Scrum Guide and turn to page 7 (of the English PDF). Fine. Nevermind. Here's a link to the section online. Let's read together. Hmmm... blah blah blah, OOH, there's this introductory bit:

The Scrum Master helps those outside the Scrum Team understand which of their interactions with the Scrum Team are helpful and which aren’t. The Scrum Master helps everyone change these interactions to maximize the value created by the Scrum Team.

See the bits I underlined? To better serve the Scrum Team, it's helpful to know how that team works, the environment they work in (...its limitations), and some of what they're working on, so you can better judge how to address these interactions.

Let's say that in the middle of the Sprint a manager tells a developer that they are suddenly on an interview pan