Doesn't have to have been a player defending his position, it could have come from higher up.
Businesses and politicians do it all the time, leak a potential change of personnel or policy to the press and see how the world reacts. If the reaction's negative then you can do something else and pretend you never honestly considered the idea that got leaked, and you don't know where that rumour came from.
If it did come from higher up it suggests that at best there was uncertainty or uneasiness around the idea of Arnautovic somewhere in the hierarchy (if you really want a player, you want him regardless of what other people think). At worst - given I think Arnautovic was considered due to Ten Hag knowing, liking and having previously worked with him - someone's already trying to undermine the new manager.
They both have a point.
The owners should have invested in the stadium, facilities and a competent football decision-making hierarchy.
But they have spent shit loads on players, and regardless of whether or not they're the right or ideal players for the club, they're professional athletes, many of whom have had some level of success at their previous clubs, and the standards they're playing at are shocking.
You either have talent or you don't, but there's no excuse for not having commitment or work rate.