Oldgoat is essentially correct about "physics".
To illustrate, take a 12"x12" aluminium sheet of .0125 thickness. Flex it in different orientations. Because it's a square it flexes equally along its width and length.
Now take a relatively narrow 2"x12" aluminium sheet of .0125 thickness. Yep: it' seems easier to flex it length wise but harder to flex width wise. That's more a function of the form factor of the sheet. The aluminium is still deflecting the same degree in either direction, it's just more apparent lengthwise. But keep in mind: the sheet still requires some force to flex it length wise.
Now take a wood ski core. Flex it length wise and width wise. Measure this flexing.
Now glue a sheet of titanial to the same wood ski core. Try flexing that along the length & width. If you measure the flex forces you'll find they will be greater - in either aspect - then they were with the plain wood core. Has to be that way. You added a metal layer which will add resistance to compression/stretch in all directions - so it will seem stiffer both longitudinally and torsionally. To be fair here, the increased torsional stiffness will probably seem more apparent - but that's more a function of the width aspect being shorter than the length (ie: width wise, less of a lever and less apparent deflection).
The rep's opinion on this is probably what most non-engineers expect to hear and his opinion is easy to understand.
To further complicate things: yes, ski designers can play with core design (thickness, materials, shape, machining patterns) and metal laminate design to modify the flex characteristics of the final composite (ie: after the metal and/or carbon laminates are added). For example, this is why some skis with metal laminates can seem softer (longitudinally and/or torsionally) and more "forgiving" than one might expect.