I don't like this at all. It seems innocent at first, but if everybody just accepts this (and judging by this thread, most do) then they will continue to see how far they can push it.
Next we will have ads in the title screen, wich people will defend because "you only see it once when you start the game", then we'll get ads during every loading screen, then we'll get ads in item descriptions or something and on and on until everybody sees it as normal.
Maybe I'm being overly cynical, but you just have to look at the state of microtransactions and lootboxes in premium games to see where this is going.