The threats she received are absolutely un-excusable. Full stop.
The joke was in poor taste and she made light of actual deaths at the hands of the US government. Then she doubled-down and mocked people criticizing her, including people who were not threatening violence. I saw a lot of the tweets at the time it was happening, and she almost exclusively was retweeting and mocking what I'll call the “genuine responses”—non-violent, non-sexist. There’s screenshots here: https://twitter.com/SeanMcElwee/status/761254572044251136
None of that above justifies or excuses the violent, sexist responses she also received, but there is more than just one thing that happened here.
I’m not a Bernie (or Trump) supporter, in case that’s a question. I’ve seen Jen’s Netflix special and really enjoyed it, which is why I’m following her to begin with.