As I recall my material science, it's not so much that steel is weak in compression but, if you have a rod of steel (i.e. much longer than it is thick), if you compress it, it will buckle and shear. As you suggest--I'd have to look up the numbers--but a large cube of steel probably has similar strength with tensile and compressive loads.

ADDED: In fact, if you deform a supported I-beam you get similar amounts of tension and compression on the bottom and top respectively at the mid-point of the beam (given a variety of assumptions).