As you point out death and rape threats are at least theoretically legally actionable. They are not acceptable under any scenario.

I feel like you are conflating sending an email to Netflix saying "Don't host material like this or I will cancel my account" and encouraging other people to send that email with encouraging people to harass, dox and threaten violence.

One of these actions is totally legal and one is not. Same thing applies to contacting someone's employer and truthfully pointing out accurate statements made by an individual which could reflect poorly on the companies repuation. It's not something I would do personally but it isn't illegal and I would even argue it isn't always wrong if you are not twisting the truth.

If you are going to say stupid stuff you better be prepared to face consequences.

Chapelle wants to make trans jokes without recognizing these jokes embolden the bigots who enjoy beating up and killing trans women. If you are going to blame the people nicely asking Netflix to not host Chapelle because they find him offensive for the fact that Chapelle receives death threats then you should also give Chapelle responsibility for the harm and death threats all transphobes commit.