GDPR, article 17(3)a: https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CEL...
> 3. [Right to erasure] shall not apply to the extent that processing is necessary:
> (a) for exercising the right of freedom of expression and information;
More precise information from WP29. See the criteria list, beginning in page 13: https://ec.europa.eu/justice/article-29/documentation/opinio... This was from the DPD era, but still applies to GDPR.
How Google handles removal requests: https://support.google.com/legal/answer/10769224?hl=en&sjid=...