Lizzie I know how you feel and I'm sure you would have intervened if Sophie was in trouble. Just take this as a lesson learned and plan on how you would handle a situation like this if it were to ever happen again. That way you won't be caught off guard trying to think of the best way to say something without being nasty.
I'm glad Sophie is back to normal and all is well. I think next time you will be able to handle it without any hurt feelings and that will make everyone happy.
Don't worry about it because we have all had similar experiences.