Csdrhrt

To state some background: I recently moved internally in the company I work for. I've been in this team for two weeks now and everything was fine until yesterday. A female co-worker, let's call her Anna, posted in the intranet that she dislikes the usage of the word "man-day" because she excludes herself.

I just commented:

And then the next one is discriminated because he does not identify
himself as a person. I find this gender mania just massively annoying
and I wonder sometimes why you always want to see a
discrimination of your own sex in everything. I can not understand it, to be honest

For me, this was just a different opinion because my point of view is that I don't care about someone's gender at all. However, in the daily (working as a developer in a SCRUM team) it was planned that I should pair with her that day what she then refused due to my comment.

I cannot understand it because my opinion and the work is something different. Did I really do something wrong here?

Appending to Twyxz answer, you should not only not have answered at all. Also, they way you answered is highly insulting in several ways:

And then the next one is discriminated because he does not identify himself as a person

She did not say this and you are trying to undermine her with some argument she did not even make. Compare it to this: You ask your boss for a $10 salary increase. He/she then responds with "oh, and then the next one comes along and wants $1,000,000 more". Would you find this argument fair?

I find this gender mania just massively annoying

It is your personal opinion that you find something annoying. Calling it "gender mania" is already a judgment on its own. Assuming you are in a workplace (like IT) were you are very likely to have a huge gender imbalance it is also simply incorrect. You might not share this opinion, but gender issues are still an issue til today.

why you always want to see a discrimination of your own sex in everything

You work there for two weeks. It is highly unlikely you could have even had the chance to observe this behaviour "always" and "in everything". Hence, your statement is in fact incorrect.

Summing up, in these few sentences you not share an opinion, you are highly insulting. This is unprofessional and you should stop that immediately. Also, you should apologize to your coworker.

Further, your whole argument is basically pointless. You might not agree with this, but there is a simple solution to call it "person-days" instead of "man-days". There really is no difference to you and your coworker would feel better. So what is the downside? Pick your battles.

Sometimes opinion should not be expressed but kept to yourself. This is one of those times. Regardless of your opinion, you should've seen that this was going to cause upset simply by the fact she was annoyed at man-day.

I cannot understand it because my opinion and the work is something different.

Exactly. So keep them seperate.

Did I really do something wrong here?

That is also down to opinion. Your judgement was wrong in commenting, you should apologise and say that you did not mean to offend Anna nor do you want this to affect your relationship and in future stay away from commenting on such things.

Politely disagreeing with the other answers (Twyxz and dirkk).

You are safer keeping politics (in this case gender politics) out of the office, yes.

The reality is that she brought it up and you gave your opinion on the matter.

I do agree you could have done this better, but, "hindsight is 20/20".

If you had gone with something more along the lines of

"Sorry to disagree, but I don't think the intention of man-day is to
discriminate you. Man-day, where the "man" comes from human just
refers to the amount of work a person can perform, which is the
definition on the dictionary. I understand your point, I just don't
agree this is something that needs changing"

Remember, having an opinion is ok. Voicing your opinion is ok. Being a moron when doing so, isn't.

Freedom of speech should be there to protect you to voice your opinion, so you can take one of the 2 options.

1 - don't bring politics to the office;

2 - Voice your opinion, but make sure it is well-explained.

Trigger warning: Voicing your opinion, even if done well, might still trigger people.

I think that when you give your opinion on things you should expect that some people would react. She gave hers about "man days" thus she should have expected a reaction.

The problem is that she started it : by saying that she feels excluded because of "man-day" she gives her opinion so I see nothing wrong with giving yours. I understand that in the workplace you should be diplomatic but if it means to let some people express their opinions and refrain yourself to express yours because you know they cannot take criticism then it's not a healthy practice. When you expose your opinion you should expect some criticism (specially when it is something as ridiculous as feeling excluded for the term "man days" which is a standard in the industry).

But on the other side you went a bit rough on her so I think that you should have an open discussion with her so she can tell you what she feels and what you feel in order to work things out.