Steven has been fighting--unconsciously or not-- White Diamond's ideas and what she represents from day fucking one. The Diamond initiative forces every single individual into a specific role/task and removing any kind of imperfection or free will about it. You do not have a choice.
Steven, on the other hand starts off as a silly, clumsy, imperfect but basically happy little kid, raised on Rose's legacy, told in the first episode that he would figure things out in his own "Steven-y" way. He wasn't perfect, couldn't fit any kind of mold his Gem caretakers (or his dad, really) tried to fit him into and as long as he learned from his mistakes and grew as a person they were pretty okay with this. They learned with him. Every enemy aside from Jasper (who was completely berserk at the time and had to be put down) has deescalated by Steven talking with them or pacifying them as a threat rather than just fucking killing them.
Meanwhile, the Diamonds/Homeworld have been shown again and again that apart from using certain tech or through brute force (which only attains a temporary win) that they *cannot* adapt to Steven/The Crystal Gems/Earth's philosophy and approach without their resolve cracking.
Blue and Yellow? As soon as it was made clear to them Steven has the Pink Diamond gem, they stopped trying to kill everybody. They then had the whole mess on Homeworld, but the damage was done to their resolve, and by that point Steven had already accepted he's not his mom and to move past Rose/Pink's grievous mistakes.
By staying true to himself to the point where his id/gemsona *is* himself and not his mother, Steven, ends up making Ms. Perfect overlord feel silly and clumsy in the moment.
It's a full circle. Maybe it would have worked better with an extra episode that is nothing but fusions going all Shadow of the Colossus on the combined Ship leading to a much more drawn out Obsidian v. White fight, but if every porkchop were perfect...