All web hosting is done on an ad-hoc basis. AWS CloudFront terms of service:
" 1.4. In connection with your use of the Services, you are responsible for maintaining licenses and adhering to the license terms of any software you run. If we reasonably believe any of Your Content violates the law, infringes or misappropriates the rights of any third party, or otherwise violates a material term of the Agreement (including the documentation, the Service Terms, or the Acceptable Use Policy) ("Prohibited Content"), we will notify you of the Prohibited Content and may request that such content be removed from the Services or access to it be disabled. If you do not remove or disable access to the Prohibited Content within 2 business days of our notice, we may remove or disable access to the Prohibited Content or suspend the Services to the extent we are not able to remove or disable access to the Prohibited Content. Notwithstanding the foregoing, we may remove or disable access to any Prohibited Content without prior notice in connection with illegal content, where the content may disrupt or threaten the Services or in accordance with applicable law or any judicial, regulatory or other governmental order or request. In the event that we remove Your Content without prior notice, we will provide prompt notice to you unless prohibited by law. We terminate the accounts of repeat infringers in appropriate circumstances."
Parler signed this TOS agreement, so they have no legal standing here.