A strong verb for harshly cutting someone down with words is berate. "He didn't just correct the cashier who gave him the wrong change — he started to berate her, calling her names in front of the whole store."
When you berate someone, you do more than just raise your voice at them; berate implies putting someone down by insulting their character. This word comes from a 16th-century English and French root meaning "to scold or blame." Often the anger behind the scolding seems over-the-top, as in "When the young man behind the counter dropped the scoop of vanilla, the manager berated him excessively by declaring him worthless and weak."