Earlier quoted context omitted.
My "data" is every woman I know in tech sharing this story with a comment like, "A version of this happened to me" or "I know so many people who have had this happen to them." Also multiple stories of women reporting harassment and being forced out of companies, as well as multiple women I know signing NDA's as a condition of receiving severance pay to avoid discussing a company's poor treatment or management of hara…
Then don't write "I guess it is common", state the number of women who told you such things. Personally I haven't heard many such stories from women in tech. Also differentiate between some colleague being interested in them and boss proposing sex on first day.
As for the latter, putting lines in the sand is a good way to be seen as not wanting to listen... I'm not saying that's what you're doing in this case, just how it comes across. Like, you've decided in advance what you want the result from the discussion to be, and no woman will be able to cross whatever standard you've chosen for inappropriate propositions (even when this is totally untrue).