Well, when a computer feels pain, detect danger, call for for help, solves new problems, etc., without human programming, then we talk.
We're not talking about that, we're talking about whether computers are more complex than ants' brains.
First of all, the entirety of an ant's behaviour is DNA-coded, so they're pretty much entirely programmed.
Second of all, we already have AI in video games which arguably behaves in a smarter fashion than an ant, and a single computer can execute a video game with hundreds of these AIs running at the same time - so a single computer can have a hundred "brains" in it which are at least at the level of complexity of an ant's brain. That pretty much proves that the computer itself is more complex than an ant's brain.
But that's something that humans programmed the computer to have. If the computer had done that by itself, then we would have arrive to what they call computer "awareness", or natural intelligence.
Humans haven't developed their own intelligence - evolution did. If the humans had done that by themselves, then we would have arrived to what they call human "awareness", or natural intelligence.