Please cite the text of a law which actually says this or any case where someone has been convicted for this under a law which does not explicitly say it.
We should obviously all have the freedoms to be offensive, because like you say, offence is essentially arbitrary. But we draw limits on that freedom all the time - for safety, libel, or public order reasons, for example. The real argument should be about where that line is drawn, and not those silly straw men about “they are going to arrest me for calling a man a man”
There are also 0 restrictions on offensiveness in the US. Any restrictions on speech are restrictions on other crimes. You can’t incite violence for example. If your straw man of what free speech means we’re true, then a gang leader could freely sit behind a desk and direct others to commit crime on his behalf all day because all he’s doing is speaking, right?...
That's not true: see "seven dirty words".
Except it's literally not; that was a deliberate misrepresentation popularized by people like Jordan Peterson. [0]
> There are also 0 restrictions on offensiveness in the US
Incorrect, see literally the entire field of obscenity law.
[0] http://sds.utoronto.ca/blog/bill-c-16-no-its-not-about-crimi...
No, it's not criminal in either place, if it's not coupled with more. Another poster replied with a link debunking this myth as applied to Canada.
And yes, laws aimed at preventing a hostile work environment, even speech-based ones, have been held to be constitutional in the US.
For a US federal example, repeatedly targeting someone with racial slurs within a workplace* will also get you into punishable trouble.
*Yes, I know certain employers, like 2-person companies, are excluded from these laws. Doesn't change the general point.
Like, calling your superior tu?