Nah, they've both been utterly shit and playing at a completely unacceptable level for months. Poor doesn't cover the kind of performances we've been seeing from Son, not even slightly.
Son was utter shit vs Leeds, Everton, United and West Ham. He was far worse than Kane vs Newcastle but got a goal. Before that he was having a significantly better season, but now for a long while has been playing at the exact same level or worse.
Son scores vs Vitesse, gets poor performance ignored. Kane scores vs Mura, this thread gets bumped because he had a bad game. They're both being judged by completely different standards because Son didn't pull the summer transfer nonsense.