King fired Fulham ahead at Stamford Bridge on the weekend, but the goal was chalked off by VAR for a foul by Rodrigo Muniz in the build-up.
But Webb, speaking on Match Officials Mic'd Up, declared: "It wasn't controversial, it was wrong. We've established some principles in terms of how we officiate in the Premier League and how we use VAR.
"They sit around a high threshold for penalising contact, aiding the flow, rhythm and tempo of the game. We've also established a high bar for intervention with VAR.
"In this situation, that guidance wasn't followed properly. There was a misjudgement by the officials involved in this situation about how that contact happened between Muniz and (Trevoh) Chalobah.
"The officials got super focused on that contact, without looking at the full context of how it happened."
Chelsea went onto to win 2-0 on the day.