Honestly don't know what people wanted ETH to do/say.
He was asked a question during an interview about Sancho not being selected.
His options were 1 - refuse to answer, 2 - lie, or 3 - tell the truth.
If he'd lied, it opens the door for Sancho to refute the lie, just like Rooney did when Ferguson said he was injured. So if he'd said Sancho was injured or ill, Sancho could have easily came straight out and said that's not true, I'm fine, available and want to play. And then a shitstorm ensues.
If he'd refused to answer, it opens the door for the press and fans to speculate and spread rumours, something he obviously wanted to avoid. It starts a huge "What has happened between Sancho and Ten Hag!" if he'd flat refused to answer.
So, he told the truth. In his opinion, Sancho hasn't been performing well enough in training and so he picked what he believed to be the strongest and most deserving 11. How this is such an insult to Sancho is truly beyond me. What an actual adult would have done is said nothing in public, had a catch up in private with his boss and said "I disagree that I've not trained well enough, but I'm going to put my head down, work my socks off and force you to pick me".
If you're siding with Sancho you seriously need to have a word with yourself.