Similar situation but I was at a work event sitting next to a colleague I didn’t know very well. We work in IT so our boss had placed a bunch of fidget toys at each table. After maybe 10 minutes of us being there, she grabbed one and said “here, you need this”.
It did actually help me that day and now I just carry one with me or else just stim with my jewelry, which I hadn’t noticed is something I do until that day.
I generally agree with your points on not wanting to create echo chambers; however, another reason for temporarily banning the topic imo is not just to block people talking about it but also to protect people who are already hurting, grieving, and generally just trying to find some sort of escape at the moment. Creating a space that will guarantee a temporary escape is nice, I think.