The goal was disallowed because Fabinho's tackle is considered to be a "deliberate save" - this does not negate offside.
A player in an offside position at the moment the ball is played or touched* by a team-mate is only penalised on becoming involved in active play by:
gaining an advantage by playing the ball or interfering with an opponent when it has:
rebounded or been deflected off the goalpost, crossbar, match official or an opponent
been deliberately saved by any opponent
A player in an offside position receiving the ball from an opponent who deliberately plays the ball, including by deliberate handball, is not considered to have gained an advantage, unless it was a deliberate save by any opponent.
A ‘save’ is when a player stops, or attempts to stop, a ball which is going into or very close to the goal with any part of the body except the hands/arms (unless the goalkeeper within the penalty area).

hmm this is what someone posted on r/soccer