Originally Posted by
The Drunkard Kid
As noted, Dragonball explicitly has"resistance/immunity to esoteric abilities from people weaker than you" as a base power, and Moro being able to hold his own against Goku in his Ultra Instinct Sign mode seems to place him at least on the same general tier as the Gods of Destruction even before he got his most recent power ups, and Galactus doesn't want to tangle with those guys unless he's been very well fed recently.
Oh, and post-power up, Moro can now copy the powers and techniques of anyone he touches on the back of their neck (the guy he got that power from was explicitly able to use that power to put himself on Moro's own tier despite being incomprehensibly weaker before doing so), and he used that to copy Vegeta's new Spirit Fission technique, which means that any hit Moro lands will tear out a massive amount of the life energy absorbed by Galactus (like Vegeta did to Moro himself, this necessitating Moro to absorb how otherwise loyal henchman to get his backed up powers back, and then some), which Moro, unlike Vegeta, can then devour himself for another power boost, assuming that he can't devour Galactus' energy directly faster than Galactus could do the same to him.