It was an indirect cause, to be sure, but had Daryl just stayed kneeling and quiet as directed, Glenn would probably still have been there to raise his and Maggie’s child, rather than just serve as fodder for a Polaroid on a Savior’s wall somewhere.
And while Daryl doesn’t wear his emotions on his jacket sleeves, this is exactly the kind of situation that is known to eat him up inside.
If you’ll recall, it was the already injured Daryl’s ill-conceived move to punch Negan in the face that made the new villain extend his initial thirst for vengeance to account for not just Abraham’s death, but also Glenn’s.