Sending troops out of The Hinterlands and forming the Kingdom of Stormwind Restoration Corps would also give him an excuse to greatly expand recruitment, lowering the human refugees' happiness with life in The Hinterlands. Once they were less happy, they would miss their old homeland even more.
Was Hinterlands short of food? Not at all! At present, The Hinterlands could more or less balance its supply and demand. In a few months, however, once autumn arrived, the fruit on the breadfruit trees in Quel'Danil Mountain Valley would ripen, leaving them with a food surplus.
But Yu Lin Bloodhawk would never touch that food. Not only would he leave it untouched, he would also divert large quantities of food from the Seaside Plain to supply the troops. Whatever the army could not use would be sold in bulk to the Allied Army, all under the noble banner of doing everything possible to support the Alliance's war against the orcs.
Judging by the timeline, the Second War was approaching its final stages, so Yu Lin Bloodhawk had to begin making arrangements for the postwar period. Of course, he would never let anyone discover his selfish motive for sending the refugees to their deaths: thinning out some of the young, able-bodied Kingdom of Stormwind refugees in The Hinterlands.
Instead, he would spout lofty reasons every day, convincing everyone that he genuinely had the interests of the Alliance and the refugees at heart, that he was a great, benevolent man of Azeroth who always kept the bigger picture in mind!
*Damn it! Do you people think I like fighting? I hate fighting, all right? If your Supreme Command hadn't demanded troops from The Hinterlands, would I be going off to fight? I'm only answering the Alliance's call. If you don't understand, don't go talking