It is more a WHY do these things work and the reason is, that the whole "security" part of these networks are build to do one thing: Make sure the operator of

It is more a WHY do these things work and the reason is, that the whole "security" part of these networks are build to do one thing: Make sure the operator of the network knows who to bill for what. Nothing else. Not to protect your ID or the content of your messages. Just and only to bill correctly. It is even forbidden for your phone to indicate IF and HOW your session is secured. Just to make sure you are not aware you're being MitMed.