As someone who shares a name with a famous person where I have the obvious Twitter username, I'd suggest that this isn't confusion, it's people not understanding Twitter.

My photo is me, by bio describes me and expressly says I'm not the musician (and gives their actual username) and yet I get mentions all the time.

That's people not understanding, not caring or not bothering but it's not really confusion about our two identities.

Confusion on what twitter handle to use is not marketplace confusion. You can have one twitter in the paper bag industry and another in deep-space fishing and you'll find people tweeting to the wrong ones. People make a guess as to a likely address and don't check.

The confusion is in the opposite direction to that protected by trademark law. He's not losing customers/whoever because they're going to the FutureStack conference by accident, when they were intending to go to his house.