Okay. Since you identify as an anarcho-capitalist, letd use some language of the philosophy you follow to maybe help you understand.
Rothbard defined private property as anything that is a scarce resource.
While a server is considered private property under this framework, data is not - first because it is words, second because it can be indefinitely copied, backedup, and redistributed.
Without getting into whether we find it justified to break into someone else‘s server or not you state that this is violence, while I believe that this is a pretty insane distortion of the term which will only lead us toward a future where words no longer have any meaning.
Its just one of the many ways in which many ancaps are inherently nonsensical: you claim words should be free and do not hurt anyone, then claim that deleting a spreadsheet is a criminal offense (which both, btw, are nothing but words).
Second, you can argue that the founder of the site engaged in direct action, and i dont have a problem with the site existing per se. But action always reaps a reaction - and in this case one that i support. Crying about it just makes you sound like a sore loser.
Fyi, since such data is usually backedup, Im sure the site is already running elsewhere again.