but being rude isn't a sackable offence surely???? There is more to this obviously.
Likely there is. OP is unlikely to share it.
But of course you ca be sacked. What we know is OP sent this email that is unprofessional. Not only unprofessional but it was a personal attack on the person
The OP feels discriminated against. That's doesnt make it true. And given at some point she thought this was ok to send, it could be that she hasnt been discriminated against at all, but this attitude is the reason she has been treated as she has been.
Let's assume OP, was up for promotion and claimed she didnt get it because she is a woman. Is it that, or is that OP thinks that email is in anyway shape or form ok. I had to speak to someone in out company the other day who says people pick on her because she is one of few women in the department. A customer sent and email chasing an enquiry they sent in July. Her response was 'I dont know about this i was on holiday in July'.
No 'good morning', no 'I am sorry I cant help you but I will see if X in my department can' not even 'can you send it again' she didnt even address them, not even their name at the top. And yes she started with the 'you wouldnt be saying its rude'. I bloody would, because it's my job to over see communication with customers. I advised her that if she would like to raise a grievance she was welcome to as it would give my department opportunity to display that we have had these converstations with men.
So whoie op sees it as discrimination. It might just her dickish behaviour.
And even if it discrimination. The person who is discriminating now has proof that she is just trying to professionally damage them, doesnt act professional and is a bully. I bet the receiver has more evidence that the OP is targeting them for bullying, than the OP has for discrimination.