Cos they hit it with a bat! Batsmen is undoubtedly correct but it sounds very radio 4 to my ear. As a kid it was batters and bowlers and it stuck. Seemed logical too; it's bowlers not bowlsmen, fielders not fieldsmen, cricketers not cricketsmen, so to a kid with a limited vocabulary it was obviously batters not batsmen. And it still sounds right and batsmen still sounds posh.
Bowled out for fifty and still win comfortably by nearly a hundred runs. Crazy stuff but well done to them.