Why does Browser still sends request for cache-control public with max-age?
When you press F5 in Chrome, it will always send requests to the server. These will be made with the Cache-Control:max-age=0 header. The server will usually respond with a 304 (Not Changed) status code.
When you press Ctrl+F5 or Shift+F5, the same requests are performed, but with the Cache-Control:no-cache header, thus forcing the server to send an uncached version, usually with a 200 (OK) status code.
If you want to make sure that you're utilizing the local browser cache, simply press Enter in the address bar.
If the HTTP Response contains the etag entry, the conditional request will always be made. ETag is a cache validator tag. The client will always send the etag to the server to see if the element has been modified.
If Chrome Developer Tools are open (F12), Chrome usually disables caching.
It is controllable in the Developer Tools settings - the Gear icon to the right of the dev-tools top bar.