When you’re filing a lawsuit against your label, let alone a big company like SM, it’s not something you just tell people. As for Kris not saying bye, had he told the boys he was leaving, there’s no telling what they would do in response. Maybe he didn’t want them to retaliate, try to stop him, or risk encouraging them to also come into conflict with the company. So when Suho claims that Kris wasn’t thinking about EXO, he’s probably got it wrong. Kris may have left the way he did with a certain logic that people aren’t seeing. Such an act doesn’t come as an irrational, senseless impulse when you are that close to people. It’s evident that he’s been thinking about this for a looooong time.
To add, Kris would have definitely anticipated being seen as a traitor to his EXO bandmates, but still left silently. Even at the risk of being hated by his colleagues, he protected them by not pulling them along with his struggles with SM. They may have paid for the situation by having to re-do their choreography for the concerts, but in the long run, they wont have further issues with SM because of Kris. He held that part of it to himself, and did it alone.