Unfortunately, I think it's salesmanship. If they would list 68*F - 74*F (which is the "correct" temp range for tropical SH sp.), they'd lose out on all the sales to folks who add SH to existing warmer setups and the sumps connected to them. The folks who recommend the proper temps usually have nothing to gain by doing so.
The other thing is that these facilities typically turn their stock over before any problems develop (assuming they're kept too warm in the first place), nor will they mention any heat-related deaths to the public.