I suspect the parent comment meant "of all things, an Intelligence Explosion by general purpose AI", which to be fair even the group set up here to study do not seriously believe in.
You are right in that It's almost impossible to deny the impact that some AI research has lead to - but that is the field of AI not the existence of "real" AI.
You might both be talking past each other
The question of whether there it will end up actually happening is unclear, but my understanding is that FLI takes the possibility of intelligence explosion pretty seriously.
This is a difficult question to meaningfully engage with, without a lot of background research. Nick Bostrom's book "Superintelligence: Paths, Dangers, Strategies" is a good entry point into the subject.