"Okay, there are not infinite bugs, but let's assume there are and make strong conclusions based the on concept of infinity..."
This guy is a fucking idiot. The VERY REASON that you don't find all the bugs in a complex piece of software is the diminishing returns on your effort to find bugs. There are a finite number of bugs, you offer the bounty and get the easiest ones found out. Then there are diminishing returns for finding additional bugs, so the payouts stop. To talk about finding bugs without acknowledging the diminishing returns on finding bugs is mindbogglingly dumb.
It is also worth noting it is not truly impossible to eliminate all bugs, it is just highly unlikely, and the efforts are constrained by the diminishing returns problem.