It is professional to continue working professionally. That is about the extend of duty. The rest is on how I judge the situation to be.
The middle ground is where thickness of skin comes in, and while it's not on you to buy in to your employer's standard, it is on the employer to set a standard.
In that respect, I don't think Tesla has been very clear here. I have no idea from this article where the actual line is.
Is "guys" still gendered? I thought it was used to refer to any group of people, male or female, pretty much since the days of "Friends".
Guys is gendered if you think it is. I've lightly offended groups of women in the past - well after Friends started! - by referring to them as "guys".
Once is a miscommunication. To continue to call them guys even after they've said they don't like being called guys would be indistinguishable from intentionally causing offence, especially considering the ready availability of other words that serve the same linguistic purpose.
As a guy I feel like it's a "meh" issue, and most of the women I know agree and use the phrase themselves, but if it bugs someone it costs me zero to avoid it.
Are you serious? You are comparing physical harassment against your body with freedom of speech? Wow... No, it does not warrant a warning. Otherwise we can get offended by random stuff and blame it on others. Plus guys and lads are used for all genders in some countries.