'actually doing a small gesture behind someone's back that neither they nor anyone else will ever know about, has zero affect on them'
That's an amoral position. Imagine if everybody went around behaving badly just because it was done behind people's backs.
You have avoided the question about having an affair etc again and again. Just because the person you are deceiving or being rude to doesn't know you are doing it doesn't make it any less wrong.
My own moral code is that there is right and there is wrong - not I am in the right as I'm not caught doing wrong.
And you also continue to miss the point that there is nothing to stop the child turning around and seeing the offensive gesture. What then?
And to those who say well it's OK to swear if it's FUN, we are talking about children. Do you really want children to pick up that message? That swearing is funny? Because surely you can see how that will hurt others and get them into trouble.
And also, I and probably the majority of parents struggle to see how you would even think about swearing at your toddler. I can see how you might want to swear in frustration because of them but swearing AT them is not adult behaviour. It is nasty, childish and inappropriate.
Toddlers cannot help being irrational and having tantrums. They cannot articulate their feelings.
Adults do not have this excuse AND they should be setting an example, modelling for children how to deal with difficult emotions.
The children who struggle with behaviour as they get older are the ones that haven't had this modelled for them.