I don't think OP is vouching for glass tanks or vivariums like what's typically posted of these topics, but just for larger tubs and thus larger racks that fit larger tubs. Which I think is what they meant by "not against racks or tubs".
I don't know what image was originally posted, but I've seen how some people keep 1500g ball pythons in 15 qt tubs and I honestly don't agree with that either. They should have enough room to stretch out the majority of their length in one direction, at the very least... in my opinion.
I keep my adults around 1000g in 41qt sterilites myself.