Welcome to the fold, toscalily.
Another thumbs up from me, Chewbacca. I am also utterly sick of being told that we are bullies, that we 'hound' people off threads, that we are 'unkind'. None of that is true - if people choose to back off because they have no answers, or because they can't back up what they say, that doesn't make us the 'baddies'.
The tern 'cis' is offensive, and we keep saying why - over and over. We are told that TransWomen Are Women (TWAW) but actual women are not - we are 'cis'. Using (or accepting) 'cis' means that we are being forced to buy in to an ideology that we do not believe.
For word geeks, the terms 'cis' and 'trans' are Latin prefixes meaning 'over here/on this side' and 'over there/on that side', so Transylvania meant 'on the other side of the wood', where 'sylva' meant 'wood'. (It means something I can't explain in chemistry too - that meaning obviously coming long after the original.) So, transpeople are people who have 'crossed over' or transitioned, and so-called 'cis' people are those who have not.
The term 'trans' is not offensive, as it is the term chosen by transpeople, but Trans Rights Activists now insist that they are the sex they want to be, not people in the sex they were born with who have chosen to leave as though they were the other.
'Cis', on the other hand is offensive, as the implication is that we are all born somehow sexless, and are assigned a sex at birth. When this is wrongly 'assigned', those who believe in this view say we can change to the other one, so everyone falls either into the category of 'trans' - people who have changed to the other sex and 'cis' - those who have stayed with their 'assigned' sex. People who reject this and believe that sex is a biological reality, not something that is 'assigned' find being shoehorned into a false category offensive. We are not being 'unkind', or 'ranting' for saying so.