@Puro's Number 1 Fan you're exactly right, mod cancelled lol
and to be fair, you couldn't make rimworld dining chairs out of stone anyway because they're all spindly and that would be hilariously difficult. imagine trying to chip that back arch out of stone

You normally don't make dining chairs out of stone because stone is cold and you don't want to sit on something cold. Because it's unhealthy (it probably isn't, but that's what I was told my whole childhood).

Holy, I was just wondering about why I can't build chairs out of stone in my dwarven colony and now, this drops.