He doesn't ultimately make the offside decisions though does he?
He clearly spoke to the Lino and presumably asked him, 1. Did the player touch it and was Williams offside?
Evidently the lino didn't think so to 1 or both and so the ref has to go by his word (which was wrong).
Can't blame the ref here, he's been let down by his staff.
The ref was well placed to see the diversion of the ball to Williams, he shuold have asked the Linesman if the play was offside in that situation. There are only two reasons the linesman could have for not giving it - either he wasn't looking, or he thought the ball went straight to the player from the first pass. If it's the first, he should never be allowed to officiate again and should say as much himself. If it is the latter, he needs the ref to tell him there was a touch, in which case the Ref is at fault. They talked, so they both can take the fault, plus they originally stood by their decision. Shocking officiating either way. Fr all it's faults, this is why we ended up with VAR, because people cannot be trusted to focus for 90 minutes.