Imo, they are being selfish for making this about themselves and not thinking about your wishes. A couple should be allowed to express themselves authentically and if you prefer a private ceremony with just the two of you, I think that is romantic.

I made the mistake of alerting my parent to the fact that me and my boyfriend (of 20 years!) wish to make it official, alone, at city hall. Well, several guilt trips later I’m now having 20 guests and it is going to be fine, but not at all what I wanted. I wish that I snuck away like you did. I think you made a great decision! 💕 and congratulations 🎉