Certainly you can carry passengers after you become a pilot. And many do and it is fun.
The trouble with the pilot in the accident which prompted this discussion is that he went into marginal and even IMC weather with innocent passengers, and then once there he didn't seem to realize that he was getting into an emergency and most of all he didn't take any positive action to try to land while he still had control of the plane and some alternative airports. Du Page was barely IMC, ceiling at 900 feet which is soft IMC, ( though it may have been raining) and Palwaukee was decent VMC, ceiling 1500 with good visibility underneath. He probably could and should have accepted ATCs offer for vectors to Palwaukee, even getting an IFR clearance if necessary, but he just kept mumbling some nonsensical replies and getting deeper into a problem. Strangely he didn't seem any sense of panic or even urgency on the radio.
If you are going to carry passengers as a low time pilot, what is great is to fly with another pilot if you can, and ABOVE ALL fly in good weather, not marginal or IMC.