How do you connect Apple TV to an xfinity wifi hotspot? It won't connect because it doesn't ask for a log in like it does on my phone or laptop.

You can't log into an Xfinity wifi hotspot using the Apple TV. The login process involves using a web browser which the ATV does not have:

How to Connect

To automatically connect at XFINITY WiFi Hotspots and get the best possible experience, install the security profile on your device. To sign in manually when you are at a hotspot:

1. Using your WiFi-enabled device, connect to the XFINITY WiFi network (network name: xfinitywifi) and launch your browser.
2. The browser will redirect you to the XFINITY WiFi sign-in page. If you don't see the sign-in page, enter a different URL, like www.xfinity.com, in your browser to be redirected to our sign-in page.
3. Sign in using your XFINITY username and password and register your device.

networks which require the user to login using a browser will not work on devices without a browser

if the hotspot you speak of works like that you can't

maybe you can lookinto if you get can your phone or laptop to share the network adhoc and have the appletv connect to them