Is this serious? Obviously, it's to make it easier to read. Reading a wall of code that's not syntax colored in a textbook is mind numbing.

Syntax highlighted code is simply easier to read. No need to consider the matter further, I think.

I want you to identify all the functions/methods and variables that are up on the presentation.

Task made simple with syntax highlighting. Task made distracting without as you'll need to read the code more carefully rather than skim it. That time taken to actually ready the code is now taking away from your ability to listen to the presenter.

Getting distracted by the color of strings sounds like an issue with boredom or ADD.

"None of this is true while we read a book or watch a conference presentation." [citation-needed], IMNSHO still true in those contexts. And as for a highlight - well, there's the, um, highlight functionality (or select, even).