Let's look at the evidence.
He has always been clear he wants to test himself at the highest level and be the best he can be. He wants to be the best striker in the world, so he's ambitious. He wants to play champions league. Now. We can't offer that
He probably could have forced a move last year. He didn't.
He's not doing a Sanchez. He's not saying pay me X or I go. He turned down the contract because he wants to play at a higher level and we can't offer it. He didn't shoot his mouth off (he just said he isn't signing), he didn't slag us off, but didn't make false promises. He kept playing and scoring (until the team gave up with 6 games left)
He's leaving to further his ambitions. Just like Klassen, Keane, Pickford, and Gify if we get him,
He doesn't deserve to be booed. He doesn't deserve a rousing reception either. Just a decent applause and hopefully some mutual respect for a player who is our best out and out striker since Linekar