These aren't "circumstances dictating" though.
This is OP pondering whether to choose just one and be done with it.
And yes, I find it equally shite that I have no siblings now, irrespective of whether my parents had that choice made for them or not. I hate being an only.
If I had been prevented from having more that one, for whatever reason, I would have been really sad about it, for them, because I know what it's like.
You'll see other onlies who are really happy being an only.
Neither stance is "right.". But I would implore OP to listen to the opinions of onlies and not the parents who think their decision to have just one child is brilliant and don't want to acknowledge that they chose what they wanted, and won't hear that it was actually shit for their child.
I had ponies, and cats and dogs and travelled loads and went to every club I wanted. Although that's because I had no one else and needed more in my life because of it. Never had to share my parents time, money, energy, priorities. Always the star of my own show. And one day no one to share what will likely be a significant inheritance. I would swap the lot, then and now, for the chance to have a sibling, however that may turn out. My parents will tell you I had the childhood of dreams and what a great thing they did just having the one.