Xtreix I'm seeing a lot of stuff in there about privacy, but not much about security. The mobile network making location tracking easy is a problem for privacy, but bad privacy doesn't mean insecure.
Insecure protocols doesn't mean you're putting yourself at risk whenever you use them. Insecure protocols in this case means nothing is stopping a third party from being able to view the data being transmitted, and potentially interfering with it. This is explained in the FAQ article you link, and the same risks apply when connecting to a wifi network not owned by you. As is explained in that same article, simply using HTTPS is enough to avoid that problem. For anything else (old apps or websites that never upgraded to using encrypted communications), use a VPN like you would on any untrusted network.
It should be noted that using a VPN for unencrypted communications means you'll be trusting the VPN provider with your unencrypted data instead, so you might prefer to avoid apps or websites that don't do encryption instead.
If you live in a country where you really can't afford to have your location tracked, then yeah, cellular network would be a security risk. but otherwise it would be nice if people stopped equating privacy with security. We can't come up with the right solutions to problems unless we properly differentiate the two (or you end up with garbage like Librewolf and Ungoogled Chromium claiming to be more secure browsers...)