system
A chat on subreddit /r/NoStupidQuestions
human
If you had said that you feel that you and her have different approaches to intimacy and value sex differently, I’m sure it wouldn’t have been much of an issue. But based on how people reacted, it sounds like you were a lot more judgmental than you are saying. 

I’m with you in that I wouldn’t want to date someone who likes to have several sexual partners and casual sex often. To me, sex is something special between people that care for and love each other. I don’t like casual sex because it’s not about love or intimacy, just sexual pleasure. 

So while I think it’s ok for everyone to have sex however they like (with consenting adults), I personally wouldn’t want to be with someone who sees sex as something you can just do Willy nilly. Different values don’t mean that you disrespect another person.
gpt
Personally I wouldn’t date someone who’s dated a lot within our friend group. Not all relationships end in good terms so is sexing someone up really worth potentially losing friends? 
Then if it ends and you start dating someone else that person will be subjected to that previous bed partner on a reoccurring basis.

For me, it’s a huge red flag that she’s dated and had sex with so many close individuals….but that’s just me.