Diners rarely research a venue. They open Maps, glance at the star rating and the two or three most recent reviews, and pick somewhere. That means a recent one-star sits directly in front of the decision, and it does its damage in the seconds before anyone reads your reply.
Hospitality ratings also move on small numbers. A neighbourhood café with a modest review count can lose a visible fraction of a star from a couple of reviews, and delivery platforms, aggregator listings and booking widgets often surface the same Google rating in several places at once.
None of that makes an honest complaint removable. A guest who genuinely ate at your venue and disliked the meal is entitled to say so. What can be reported is content that breaks a Google policy — a review for a different venue, a review from someone who has never ordered, abuse aimed at a named staff member, or a review used as leverage for a refund.