There comes a point where we have to accept that all our decisions will not find approval with every other human being. It doesn't feel nice when we bear the brunt of this disapproval but we need to be strong in our decision and know that what we are doing is right. In the end, it really is the mother's choice as to whether they have numerous scans or not. For whatever reasons. Just like it is their choice to be having a baby. Sure there are some people who may not be in tune with their bodies, but so what? I think we are lucky to have the option of a dating scan. I chose to just let my body work and not worry about when I was ovulating etc. I did know when my AF was supposed to be due and I knew that they were pretty regular, but I had no idea if that meant that I would give birth on a particular date. Babies come when they want anyway, regardless of whether your dates are right or not.
I'm sorry you weren't treated nicely by your sonographer. A lot of the time, they haven't received the right training in dealing with patients especially when it comes to the sensitive nature of pregnancy. I had fantastic experiences with most of my scans but that's because I paid a fair bit for private after bad experiences with the public system.
At the end of the day, it's wonderful news that everything was good with your scan. Best of luck for the rest of your pregnancy xx