It's not about Lukaku, it's about Conte's attitude towards his two main strikers. It doesn't feel right. Just like the Eriksen treatment didn't feel right.
Being subbed off in a big CL home game as the alleged star of the team for a teen who's never played in the competition despite still early in the game, was a humiliation for Lukaku. Especially given his atrocious performance in the first game and what preceded the game in question. I'm just saying that this sort of happened to Lukaku then. But that was it. The Slavia game is a non-factor. You only know it because Lukaku said it. There's tons of shit that's being said that no one says outside. Lukaku probably got told off by Conte for saying that in public.
Whereas with Lautaro it was a really bad gesture by Conte. It's annoying having to compete against the teacher's pet, so I get Lautaro's frustration. His performance wasn't completely terrible, he just wasn't in good form. He still tried and run a lot, I honestly was very surprised and couldn't have thought that it was possible to see him out. Perisic on the other hand, sure.