I realized this while contemplating why political assassinations of heads of state didn't really start to happen until the late 19th century. It was because the average person didn't have access to the kind of technology that would make killing a person that easy. Louis XIV didn't have to worry about some random proto-socialist peasant killing him with a musket during a speech or religious ceremony etc. But since technology is downstream from the elites, eventually the average person gains access to it. There is always some delay between the tech being used by the government/military, and it becoming ubiquitous and too cheap to justify/make it possible to keep away from the public, but it does happen eventually.

Consider computers. They were theory, then they became applied in very specific specialized military applications, then science, then offices, then rich people, then average people from developed countries, and now you have people from third world countries using iPhones to film arranged marriages and upload them to Instagram, ISIS using the internet to recruit, human traffickers using the dark web, etc. All because of how cheap and easy to produce and acquire computers became over time. Downstream, from governments and the rich to even the most common of people. And since many people are evil, once that tech reaches the general population, it WILL be abused. I.e, I'm just a normaI private citizen from a non-ultra rich family, but I could literally go to Twitter right now, and Tweet something about a shooting, a bomb being in some populated area, threaten to assassinate a public figure, etc. and cause a fair amount of chaos, all with my fingers, a cheap smartphone and a public wifi spot (this is just to give an example of how dangerous technology can be, I have no such plans, feds who are reading this).

The only argument I have against this is: Nuclear weapons have existed for almost 80 years, and their technology and required components to produce them are still impossible to get by the average citizen, or even some major powerful organization. Also, while my Twitter example still stands, the average person with an average home PC still can't do cyberattacks and DDOS attacks against government computers. Maybe future governments will find ways to keep truly destructive tech away from the general population, no matter how cheap and feasible that tech becomes, like they're doing today with nukes (after all, why doesn't ISIS have nukes?). Maybe they could keep their materials artificially scarce, or have a complete monopoly over their production etc. Then again, firearms were invented in 1400, common people started to use them for political assassinations in the late 19th century, and, before that, the first time in history when it became obvious that large numbers of common, non-specialized people could use firearms en masse to disrupt the government's monopoly over force was the French Revolution, 400 years later. It took 400 years, but firearms did eventually become accessible by non-governmental actors.

Yeah, I definitely see this. Humanity's technology reaching such high levels and ubiquity, that the average person, not someone connected to government, big business, elites etc., but just some random jackoff with a decent income, simply has too much power. Imagine nuclear weapons becoming so cheap and easy to make, that governments would have to constantly crack down on people buying and selling them, like with drugs. Problem is, using them just once would be enough to cause great devastation. Or, as you mentioned, engineering viruses without needing very specialized equipment. Hell, it doesn't even have to be that accessible and reach the public. Just so long as that dangerous technology downstreams from the government level to the "powerful organizations" level, that is enough.

And the fucked up thing is, I see no solution other than halting technological progress, or complete authoritarianism. Once/if the singularity happens, in the average person WILL have near god-like power. Energy WILL become cheap to the point where the average consumer can build pretty much whatever they want in their house. Again, other than primitivism or authoritarianism, I see no other way to save humanity from dangerous technology being too accessible.