Let's dig deeper, with your examples:

Crypto: If you're a normal user, you can be private. If you're criminal, you'll get to cover some of your tracks. The other effects are secondary and indirect.

Anonymous content sharing: If you're a normal user, you can share stuff. I personally share stuff this way in HN. It keeps my cloud accounts tidy. It can be used for other nefarious purposes, but it's effects are again secondary.

Free Speech: It shall also be used by yucky people, so we can improve our civilization, systems and ourselves further. It causes a lot of pain I know, but alas, humans probably need it sometimes to evolve. We're lazy otherwise.

UBI: I think it's a neat idea. I can't think any bad examples, sorry.

Consumer Grade GPUs: I don't think using a country's worth of energy to speculate on something's value is hardly efficient, so I'll pass. However, again its effects are secondary.

In all your examples, the receiving party is narrow. The receiving party's number grows because of secondary effect. However, web technologies bring everything to your home, including exploits and abuse.

It's a big can of worms for 1-click and 0-click exploits. "Oh, the web browser was not on the foreground, how my data is exfiltrated?" yeah, webusb/webbt/webaudio.

Crypto cannot directly harm you, neither GPUs. But I can get into your home and violate your with every privacy right with a couple of little, neat technologies.

Maybe you're right. We shall let these technologies loose and allow everyone to snoop into everyone's devices. That'd be equal and democratic. Maybe exploited people will like it and allow more of it. Like the most recent Facebook breach...

While we're at it, I really like the glow of Cherenkov Radiation. I'd like to build a small, fish-tank sized reactor with lead-glass sides. I won't use the material for any other reasons. If only they let me...