Death threats are always inexcusable & unjustifiable; that said, what exactly did he post? Perhaps some forms of content attract way more spite and hate than others?

I think in this day and age, with the combination of a young & unruly audience plus the edginess allowed on many platforms, you're going to be exposed to shockingly unfiltered behavior.

I also think there are specific forms of content (and your strategy of engagement online) that can mitigate this, e.g. posting political content versus some non-topical artwork.