OMG I can't believe that other lady reacted like that. Speaking as someone whose ds gets bitten regularly at nursery I can honestly say that she is hopefully in the minority of this ignorant attitude. My ds is bitten everyday at nursery, however, he is bitten because he is a pusher! We are desperately trying to calm his pushing down too but as I am constantly told, it is probably a phase and tbh he is rarely pushing now. We just stood our ground with him, let him know what he was doing was wrong and worked in conjunction with the nursery in correcting his behaviour.
Please try to ignore the likes of that stupid woman - for all you know, her ds may have hit your ds and he was retaliating. I know it's wrong but she should know that toddlers aren't bloody angels and if they're not biters then they are quite possibly pushers, snatchers, scratchers, wrestlers or all of the above!
Have a word with nursery and try to put her comments to the back of your mind.