Motcha, while achav was an oved avoda zara, it doesn’t say that his army had people who were involved in ervas davar – that’s what the pasuk says will cause Hashem to turn away r”l.
The Israeli army, however, does and is proud of it. The army itself was designed to be an indoctrination tool and place of iniquity – in the same book, rabbi shapiro cites manu sources attesting to the activities of the average IDF soldier. Rav avigdor miller cites in “awake my glory” abortion statistics, that most women are members of the army at the time of their infanticide.
Therefore, any success they have is from the sitra achra, since Hashem says he turns away from such an army. The brisker rov, alternatively, said that the yidden who daven and are frum are protecting the rest…in effect, we are safe in eretz yisroel in spite of the army, bzchus the yirayim ve’shlaymim.
Pick a shitah; both are daas torah.