It is not a given that we should allow computers to exist, the risk of harm is too great.

It is not a given that we should allow vehicles to exist, the risk of harm is too great.

It is not a given that we should allow hammers to exist, the risk of harm is too great.

The argument, even if it weren't moot due to the cat already being long out of the bag, is recursive all the way back to the discovery of fire. As a species we already regulate things that can cause harm in ways that are commensurate with the potential for that harm. Some are regulated more, some less, depending on the region. But all these things exist regardless; you have to decide whether you're comfortable with elites and governments being the only people who should have access to this, especially given that they have a history of not keeping your best interests in mind, or whether it should be democratized and available to all (like most other tools in existence)

I do not believe nuclear weaponry should be "democratized and available to all"; it should not exist. Likewise AI that's capable of step-by-step bioweapon creation for the average person. It shouldn't exist in the hands of governments, either.

This is not a slippery slope, nor do I think your attempted reductio ad absurdum is valid: we can talk about AI and nuclear weaponry and judge them differently than we do computers and hammers.