I don't see where the letter says or implies there was direct abuse. It just says abuse.

I interpret it as meaning that the author believes that indirect abuse, including hearing sexist jokes while in the workplace, should also be "absolutely unacceptable."

That is not a novel or even rare viewpoint. For examples that I easily found:

"Sexual abuse includes: Telling sexual jokes that make the victim uncomfortable" - http://haventhedalles.org/sexual-abuse.html

"Sexual abuse ... [can even take the form of] telling sexual jokes at the victim’s expense." - http://www.flaknelaw.com/minnesota-family-law/domestic-viole...

"[Patterns of] Sexual Abuse .. Makes sexual jokes about women" - http://www.wcsafeharbors.com/domestic_violence_patterns.html

This is why documents like http://www3.uakron.edu/lawrev/robert1.html include things like:

> Professor Catherine MacKinnon advises companies to warn employees against posting suggestive photographs, telling sexual jokes or making innuendoes, or romancing subordinates. ... Finally, she says that the company should prohibit everyone in the company from retaliating against a worker who files a sexual harassment complaint.

Do also note that this firing treads close to the anti-retaliation laws. Quoting from the EEOC at http://www.eeoc.gov/laws/types/facts-retal.cfm :

> An employer may not fire, demote, harass or otherwise "retaliate" against an individual for filing a charge of discrimination, participating in a discrimination proceeding, or otherwise opposing discrimination.

I am not saying that this firing is in violation of the law and EEOC rules, because I'm not a lawyer and I don't know the case history. But my naive reading of the EEOC Compliance manual, at http://www.eeoc.gov/policy/docs/retal.html#IIpartB:

> Public criticism of alleged discrimination may be a reasonable form of opposition. Courts have protected an employee's right to inform an employer's customers about the employer's alleged discrimination, as well as the right to engage in peaceful picketing to oppose allegedly discriminatory employment practices.

suggests that posting those pictures is likely a protected action. If so, then while you may think it's "unprofessional", it's not a valid reason for firing someone.

(The laws are made even more complicated by a balancing act between what a "reasonable person" would expect, the understanding that an employee don't know all of the details of the law, and more factors. Like, Richards's job requires going to conferences, hence PyCon is part of the workplace, but SendGrid doesn't have control over what happens at the conference, so discrimination claims filed to SendGrid are useless.)

I'm pretty sure you don't know how the EEOC would handle this case either, since your #2 does not reflect at least my limited understanding of the relevant laws. Protected opposition can include doing things that are "unprofessional" and things that cost others money (the EEOC's example is a production slow-down).

Also, you brought up an account of how "she has frequently sidestepped the right channels", but unless they were related to her job, I suspect that they cannot be used to fire someone. Specifically, Colorado law C.R.S 24-34-402.5 ("Unlawful prohibition of legal activities as a condition of employment")

(1) It shall be a discriminatory or unfair employment practice for an employer to
terminate the employment of any employee due to that employee's engaging in any
lawful activity off the premises of the employer during nonworking hours unless
such a restriction:

(a) Relates to a bona fide occupational requirement or is reasonably and rationally
related to the employment activities and responsibilities of a particular employee
or a particular group of employees, rather than to all employees of the employer; or
(b) Is necessary to avoid a conflict of interest with any responsibilities to the
employer or the appearance of such a conflict of interest.

(SendGrid appears to be a Colorado company, but other states have similar laws. See also the note 'This section applies to lawful, off-duty conduct, even if it is work-related. Insofar as the section refers to "any lawful activity", it can be presumed that the general assembly meant all activity without limitation. Accordingly, damages could be awarded to person who was terminated for making a complaint off the premises of the employer during nonworking hours about the safety of a work site. Watson v. Pub. Serv. Co., 207 P.3d 860 (Colo. App. 2008).')

Thus, it really does read that if Richards is fired because of any of the reasons you gave in #2, then it's likely an unfair and illegal employment practice, and Richards can sue and win.