-SWATTING of competitive Gamers.

-Cyber bullying (not just limitied to those instances that end in suicide)

-The stalking and death-threats to Black Lives Matter organizers.

-China's "social credit score"

-The need for Hong Kong protestors to hide their identity.

I don't have time to post specific URL's to substantiate my claims, but I feel I've given broad enough categorizes to convey my meaning.

The internet is a creation of the mind. Its impact is felt by the mind, and is capable of creating mental health problems in people. See the old Facebook story about how they manipulated people's feeds to provoke an emotion from them for an example.

The internet also enables mass communication. So you can massively communicate in such a way as to impact the mental health of a massive number of people. Most people who use the internet regularly are bombarded with this type of communication, mostly in the form of ads and sponsored content.

There are undoubtedly many parties who've realized they can use this to their own ends. By using the internet to actively impact the minds of other people using the internet, people have weaponized the internet.