If there is anything David Moyes is, it's strong. He's hardly one to be weak willed.
He's not going to come in and slate players, saying he'd listen to offers or down someone's chances of making it at United before playing a single competitive game! Honestly..
As for Welbeck, yes, he was poor in front of goal last season, but his overall performances weren't bad. He'd beat people, his passing was good and he looked quick. You're making out like he was bad in every way, he wasn't. He's not going to be a world beater, but he's sure as hell good enough to be in the squad. If he starts finishing his chances (like he used to) then he's a great weapon to have. Plus, he's Manc born and bred, he loves United and he's passionate to the club. You should kill for that kind of loyalty. Especially when you look at the Rooney saga.