While the hosting location may be decentralized, using Cloudflare introduces a level of centralization in the way Internet traffic is managed. Cloudflare acts as a central point through which all incoming traffic is routed before reaching your decentralized server. This centralization is evident in the fact that Cloudflare controls access to the site, providing security measures, CDN services and acting as a proxy server.
Without Cloudflare, hosting can indeed be decentralized, but the inclusion of this proxy service means that a central entity (Cloudflare) plays a key role in handling and directing traffic. This introduces a level of centralization to the overall service, even if the hosting itself remains decentralized.