On some level, Cowslip knows that this is wrong. He doesn't admit it, even to himself, will never let anyone see, but he knows. Children should not have to live in constant fear of being threat one the men take away, because the men do take them away. Oh, never too blatantly, never too obviously; more like a silent disappearance in the middle of the night. One day someone is there, the next they are gone.
Cowslip never lets himself think where they might have gone to, and he won't let anyone else think about it either. That's why no mentioning their name, no looking at their work, nothing. It's better if they never had existed. That's what Cowslip tells himself, anyway, and sometimes, it even sounds convincing.
It's not like they live a bad life. There's food, as much as they can eat, and time to do whatever they want. Painting, sculpting, gardening, anything at all. There's just one thing that all of them know they should never do: never go walking in the garden. That's where the monsters hide, great steel cages that will trap them in and pits that will snare them and take them away, out of sight, out of mind, out of memory. The traps don't stay still, gathering wherever the children gather, especially if someone finds a quiet spot to them self, especially if they're pretty. The pretty ones go first, Cowslip knows, and he never lets himself think why.
Once the men have them, wherever the men have them, whyever the men have them, they will never, ever, be coming back. What matters most to Coswlip, is that it's not him.