“I ate a coworker's yogurt. Their name was on it, in marker. An hour later they emailed the whole office asking who took it, and I replied, ‘Oh no, that's awful.’”
Majority opinion
Yes. Not for the yogurt. The yogurt was a lapse; people get hungry near fridges. “Oh no, that's awful” was a choice. You had a clean exit, which was silence, and instead you wrote yourself into the crime scene as a grieving bystander. That's the part we can't let go.
Minority opinion
No. You're a coward, which is different and far more common. Nobody in the history of office email has confessed on a reply-all thread. Replace the yogurt. Say nothing further. Let the thread die the way all threads die: unanswered.
Sentence: Replace the yogurt. Buy two. Leave them without a note.