Kessel DID lead in goals and points, by 3 (22 to Sid's 19). This is true.
Crosby had 4 assists in the SCF including 2 in game 7 and one on the cup clinching goal. No, he didn't score in the finals, but Phil only had 1 (and 3 assists) himself in the finals. Not exactly much of a discrepancy (and yes, maybe predictably, I'm gonna say it, against weaker competition).
Every year, we're told it's what you do in the third and fourth rounds that truly matter for CS. Well, I already mentioned what Sid had in the SCF. In the ECF, he had 3 goals and 2 assists in 7 games vs the Lightning. Kessel had 4 goals and 2 assists. So, in the last 2 rounds, Kessel outproduced Crosby by a single point. Nevermind that Crosby also scored 3 of the 4 game winning goals in that ECF.