I'm still not feeling you. I don't get it.
Culture of acceptance is great. If you support that, then why are you supporting stim-breaking? Why not accept that the child might be enjoying the new thing in his/her own way instead of trying to make the child "get over it" and enjoy it your way?
Do you see what I'm saying?
In the end I'm a teacher. I'm a teacher who supports a huge amount of choice and a culture of acceptance, but I'm also someone who, in the end has specific goals for my kids, and I do want them to engage in a wide variety of activities that support those goals. Sometimes stimming gets in the way of that. At the same time, I see stimming as goal directed behavior in itself, and I want to respect that. So if a child's stimming is getting in the way of a goal I have for that child (e.g. if I want the child to play with playdough because it will develop their fine motor skills, and because I think it might be a great way for them to get sensory needs met, and because I what I know about this child tells me that they're probably going to love playdough, but everytime I bring the playdough out they jump and flap and don't touch the playdough) I'm going to work on being around other kids playing playdough without flapping. I'm not going to force it by say holding them down or ordering them to stop jumping, or threatening to put them in timeout. But I will do gentle things like inviting them to sit on my lap and watch, or waiting to pull out the playdough until they're engaged in something else, or pulling out the playdough when they've just come in from outside and they're a little tired, or putting the playdough table next to the water table because I know they like to splash and watch things simultaneously.
I'm not an unschooler or a Subdury teacher, although I respect those points of view. And I don't believe it's contradictory to love someone fully and accept who they are, and also to want to help them grow. When my DS was 3 he was the most perfect child in the world (to me, which is all that really mattered) and I still nudged him gently towards potty training, I don't see those things as contradictory. I think my 9 year old is absolutely perfect, and I still take him to the library and help him find books to read over the summer and keep his skills up.
I also want to add that for some children, stimming can be a sign that they're uncomfortable. My own son went through a period when he was having chronic pain and his sensory seeking escalated dramatically. Did I want that to end? Of course, because when it did it meant he wasn't hurting. Billy the little boy in my last story would flap and toe walk when he didn't feel completely safe. So when we brought the dog he loved to the gathering, and he plopped down next to her and ran his hands through her hair I saw that as a positive -- it meant that felt better and more relaxed. On the other hand, he had other stims like watching balls roll and sand fall that he did for the sheer joy of them -- and so we handled them differently. We brought new things into the classroom that incorporated the same elements (glitter to sprinkle in the art center, a water wheel that spun in the water table, ramps and little balls in the block center, etc . . . ) in the hopes that it would get him moving around the room, and it did.