I agree that the email is mean-spirited and unpleasant, but "I'd like to kick the shit out of him on twitter" is clearly not an actual threat of violence.

Fair enough. As the comment below points out, more likely she had in mind the idea of personally ruining him, as she has tried to do (and partially succeeded) to at least one other person in the past.

Tanden may have used her high position to get a left-wing labor blogger fired for calling her "scumbag neera" over her alleged role in 'reforming' welfare in the '90s, ultimately harming those in extreme poverty.

Edit: the blogger was also an expectant father.

This only substantiates that theory.

The blogger had a full-time job. The blogging was just a side thing. Neera denies having him fired (as opposed to the org firing him on their on decision). Source: http://www.slate.com/articles/news_and_politics/politics/201...

The blogger was subsequently fired from the full-time position.

Neera lies, a lot: http://coreyrobin.com/2016/06/25/neera-and-me-two-theses-abo...

Citation for the first claim?

Twitter. Unfortunately, I don't have a link handy. You can also go to the blogger's personal site and find his resume showing an end of full-time employment.

There were a number of people who did not like his combative style in disproving liberals' claims, who banded together to complain to his full time employer.