My 8 month old dd has a high pitched scream too which she does when she's a bit bored or grumpy. You have my sympathy as it does seem to get other people hot and bothered and makes trips out a bit difficult.
I'm shocked at how nasty that woman was though, totally unecessary. For one thing, no 6 month old baby knows how to 'behave', they are way too young to be 'controlled'! Babies crying and screaming is a fact of life, all babies do it at some time and you never kniow when that time will be.
Try not to be upset. She is a nasty old bitch and probably has a very miserable life if she gets her kicks putting other people down like that. You on the other hand sound like a thoroughly decent person.

She was a crazy old
bitch woman.
Ignore her!As you say your LO is only 6 months and all the babies of six months I know/have known are champion screechers

My 6 month old dd spent ages screeching - and she is quite high pitched. We were at a restaurant having lunch, supposedly a baby friendly one. A woman of about 60+ came up to me and was really agressive and said that babies like mine shouldn't be taken to restaurants. I was very taken aback and really didn't say much. Then a while later I went up to her table and said that she should not speak to people like that. She insisted that children who didn't behave shouldn't be taken out. I said that my dd was a 6 month old baby - a baby - how do you discipline a baby! She was nasty and her husband also joined in and they both insisted that they had 3 kids and had never taken them out unless the kids behaviour could be controlled.
I was really upset and still am - it just happened earlier today. Why are people so nasty or was i wrong?