Sure, but how do you feel about a person's right over their personal information being systematically collected by their government, several large corporate entities, and a dozen or so international spy agencies? What about when this information is used to economically bind them into submission?
Ah, but that's about how the tools are used, not what they are and who has them.
I believe, any entity, from a mere individual to a government agency or multinational corporation should be free to possess any software tools they may desire. How they use those is another matter.
I do "spy" on my own traffic on my own network running on my own hardware on my own premises. I've had some audits for possible malware/spyware, did reverse engineering protocol analysis, etc - and believe everyone should be able to do that. I shouldn't be able to do this on someone's else traffic without their informed consent - nor technically, neither legally (I believe, both of those aspects are important).
As for your question - I don't like this, of course. Don't think there is anyone well-informed and in their sane mind who does.
We're talking about what are essentially cyberweapons and surveillance tools.
Why can I not own a nuclear warhead, as long as I promise not to do anything with it?
Why can I not put cameras and 3D radio imaging equipment up across the street on a small private plot of land and spy on you and your children's home without being visited by the police at your request?
If you don't have a problem with how those two cases are legislated then you might be able to understand how this could relate back to software.
Should you have access to any program you want? I guess so, if you can get it in a licensed manner. If it's FOSS or something similar, that will be easy. But using these tools to collect surveillance data and PII is an entirely other issue because of the potential weaponization of collected data and the harm that can result from it.
I supposed I did not fully understand what the OP was asking, because I do believe you should be able to own these tools and test them on your own equipment, and that the issue is that we need to ensure proper protections against these tools are in place for the average uninformed user.