Global Rules

Now I have set the global rules using the wizard to block all incoming connections.

I am confused about one thing.
Can anyone explain how can, for example teamspeak server be blocked from incoming connections (so i have to open a single port in the global rules) but i can play an online game as normal without interruptions (and without opening ports).

To my understanding everything communicates on the internet using an IP and PORT. So shouldn’t the block all IP rule prevent everything from receiving anything.

Please help as this is confusing me.