That still isn't a compelling argument to avoid development of those technologies.
Problem is on how to implement those technologies.
If you go by numerous people on this board alone, right now, there is a mindset present that implies numerous techs would be tried used for betterment of our society.
If you take a look at the government for example and rich people in power, then yes I agree that some techs that were specifically designed for 'abusive purpose' will be utilized as such.
Abuse of technology can be interpreted in many ways though ... such as rich people and government having access to about a decade or more advanced tech while the general population has to make due with what is given to them.
Right now though, I don't even think we reached a proper early 21st century development stage.
Numerous technological development and scientific research went under because of nothing other than money and people in power who don't want to encourage new technologies being implemented.
Money is at the core of our problems. It always was, and technological/scientific growth will continue to suffer because of this (let's not even go into the debate on how religious individuals in power who have poor understanding of technology also are a factor).
We live in the early 21st century and we still have rampaging diseases and poverty.
Don't tell me it's beyond our ability to solve these issues, because it's not.
We have not just the resources but also technology (such as it is) to do so.
The prospect of quantum computers is excellent ... although I'm afraid it will be a while until we see them fully realized.