Nobody can prove unicorns don't exist. Nobody can prove trolls don't exist. Nobody can prove vampires don't exist. Nobody can prove leprachauns dont exist. Nobody can prove terminators from 2029 don't exist. Therefore, they all must be real.
There is a problem with this line of argument.
Let us say, for example, that I made the claim, "innumerable living organisms exist." One could in turn charge me to prove that this is a fact. And so I respond that nobody can prove that innumerable living organisms do not exist. Now here is the problem: once someone argues that nobody can prove the nonexistence of unicorns, trolls, vampires, leprechauns, etc. we run into something akin to a category mistake. These particular entities (unicorns, trolls, etc.) may or may not fall
into the category of the "innumerable living organisms." It is not that they are a category themselves, analogous to "innumerable living organisms." Instead, they are
particular entities, with very specific characteristics.
Similarly, "God" is a very general concept of a supreme being. That God may have the form of a unicorn, troll, leprechaun, vampire, terminator, or whatever else is an entirely separate point of contention from the existence question.
Unicorns, trolls, vampires, leprechauns and terminators are not, regarding the question of existence, comparable to God in the same way that they are not comparable to the existence of "innumerable living organisms."