With due respect, the Great Filter is a hypothesis, not a theory.

That being said, I agree. I read in a similar thread yesterday someone confused how this would be bad news rather than good news—that there are many other intelligent species indicates that such a filter either doesn't exist or is very easy to pass. But, like your point does, I think it's important to recognize that such a "good news" position is predicated on the notion that we as a species are already past the Great Filter, rather than that we're still behind it and the others are ahead.