“It is important to mention that some bugs are just not reproducible at all. They can just be ignored.”
I think that when you can’t reproduce a bug, the right response is at least sometimes to look at the relevant code and determine how the bug is even possible, and work until you’ve ruled out all but one cause. Another possibility is to determine what information you can add that would diagnose the bug the next time it happens.
I’m not claiming that every bug will succumb to that treatment, but some do. I’ve had bugs that I’ve only ever been able to reproduce after I had designed the fix.