In earth's northern temperate zone, where oil per-capita is consumption is highest, there are plenty of marginal croplands and rock strewn hillsides suitable for productive aspen stands (as pictured) or similar species of trees or woody shrubs, making the moral and the practical delineation of this idea imminently practical for large scale fuel production. Non-cropland is much cheaper to control or manage. Targeting non-food biomass as a feedstock, then, is Just what we'd expect from Shell if they'd done their scenario thinking around business parameters. The morality statement, above, would be consistent with that, but not the only driver.
We should also consider other possible motivations for the Shell representative's statement. Perhaps a bit more time would help to make a proprietary biomass-to-ethanol process work out? Perhaps an argument is needed to spread government incentives for ethanol production around more fairly, benefiting more than just the agricultural sector?
Put all these ideas together and we see the makings of a sustainable fuel system in early design stage.