If Matthews goes in the break without teammates, he has no chance to win the stage as all the other riders wouldn't want to get to the line with him. And he isn't Van Aert or Van der Poel who can just ride into the sunshine (also, and you can definitely fault him for that, that is not something he ever even tries).
I don't think they necessarily had the stage today as a target from the off and considering what happened yesterday, it was definitely reasonable that they didn't chase all day. Okay, then maybe they should have other guys in the breakaway but don't come telling me that having a lone Hamilton or Howson in a break of the day would give better chances than going for Matthews in a sprint.
Then they have seven riders still in the decimated group and because Matthews had been dropped on the hill, they couldn't get to the front until after the descent. It wasn't like they were deliberately waiting until the break was almost out of reach just for the lolz. Then Matthews made a wrong split-second decision when he decided to stay on the wheel of Mezgec who simply couldn't bridge back up to Bagioli's back wheel. And that was where he lost the stage. But saying that that incident is fool-hard proof of the fact that Matthews can never ever win a bike race ever again is just tiring and reminding of when people criticised Bora for working for Sagan on the stage in last year's Tour where he ended up being blocked in the sprint by Hugo Hofstetter. Such things can happen but they can't be used as proof that the team of the sprinter in question are in the wrong with their strategy.