Here's another one of those dumbass comments that theists make and it's dumb for a couple of reasons.
First of all, it's not true.
Look up virtual particles and see for yourself. These are subatomic particles which exist for a short time and then annihilate each other again, quantum fluctuations in the vacuum of space. They aren't caused by anything. They are energy that temporarily particalizes and then returns to energy. What are they caused by? Random probability, and they are permitted to exist by the Heisenberg Uncertainty Principle.
Cause and Effect is a function of Classical Mechanics, not modern physics, with all the Quantum Theory and everything that we know about today. On the macroscale, it is simply an approximation, a generalization, an assumption that is made based on observation; and even on the macroscale, we have no way of knowing it it is literally always true all the time (and mathematics suggests it's actually otherwise). On the microscale, it's simply not true; in fact, it's rarely true.
Of course, the usual argument against such a statement is if this statement everything is caused by something is literally true, we are led to an infinite regress and supposing that there is a First Cause is to deny the truth of everything even before we've begun. If literally everything has a cause then so does any postulated god. We have done nothing then to solve the problem. And changing the statement to nearly everything, does nothing to suggest that god, if it exists, must have been the cause of the universe or anything else for that matter, because god might be the cause of everything we see, or some other "uncaused cause" might be.