Very odd line of argument for me. Is it lazy to say Mane and Salah have had great seasons because of the numbers they've posted? Sometimes a spade is a spade mate.
City have had a poor season and their defence has let them down on multiple occasions but De Bruyne has dragged them kicking and screaming to a level of quality that has at least seen them recover to a comfortable 2nd place. What's lazy and wrong is arguing that because Man City haven't won the league, he can't have contributed to their season. By definition, this award is supposed to be based on the output of the individual, not a judgement on what they achieved along with the team around them.
Henderson has not been better than De Bruyne this season. Nobody can really objectively look at this season and say Henderson has been the best player in the league. He hasn't even been the best player for his team, Mane has in my opinion. There's a slice of sentimentality behind this award and the people who chose Henderson have done so for other reasons on top of his performances on the pitch, which is fine if that's what the award is going to be for, but I'm not having people pretending that this is the right call based purely on his individual performances on a football pitch.