Free Wi-Fi network: how to autoaccept (robotic click) wifi policy web page?
I don't think you looked very hard in the Play Store. I found several apps which look like they'll do what you want. (I searched on "wifi auto login".)


Wifi Browser Login "This app will automatically detect if your WiFi connection requires browser login.
It can be configured to either notify you or automatically popup a webview for you to login."
WiFi Web Login "Automatically logs you on to any WiFi hotspot, hotel WiFi, guest WiFi."
WiFi Auto Login Lite "WiFi Auto-Login automatically logs in your Android device into some of the most popular FREE WiFi hotspots, eliminating the need to deal with that annoying WiFi hotspot login page!"
...plus a bunch more. There's quite a few that have a very fine focus, such as one just for Starbucks.