make men out of them

manは基本単語ですが英英辞書で調べてみると，a man who has the qualities that people think a man should have, such as being brave, strong etc（LDOCE）とあるように，「一人前の男」（『プログレッシブ英和中辞典』小学館）といった性別以上の意味が含まれます。そこからmake a man (out) of ~は「〈少年青年を〉自信を持ってふるまうようにさせる」（『プログレッシブ英和中辞典』同上）という意味を持つようになりました。ここでも「生徒に自信をつけさせたかった」と解釈できます。（Koyamamoto）

Basketball coach viewed as godlike figure
Successful coaches rarely questioned over methods; students at strong schools know what to expect
OSAKA--The student who committed suicide the day after he was slapped by the teacher coaching his basketball team has exposed a remnant of old-style coaching reliant on the use of physical punishment.
In particular, coaches posting exceptional records tend to become self-righteous, with no one daring to challenge them. Students committed to the club are often emotionally troubled.
... The coach gained a reputation for building teams by emphasizing defense and an up-tempo running style. The coach won the trust of parents, saying: "I'd like to emphasize the process of winning, rather than aiming solely at winning. I'd like to treat the boys the same way I treat my own child and make men out of them."
http://www.yomiuri.co.jp/dy/national/T130115004043.htm