Plus, he didn't particularly have much of a choice. That was because the moment he appeared, he was assaulted by a suppression from above.
It felt like even the air was rejecting him, and it was the first time that he had experienced such a thing.
But this was also the first time Ryu was stepping into a world in this fashion.
Back when he first came from Sacrum to the True Martial World, his foundation had been took weak and inferior of the latter to take seriously, so he didn't face any suppression. And, as he rebuilt his foundation, he was doing so with the laws of the True Martial World, so, of course, he wouldn't be rejected.
When he returned to Sacrum, he had been returning to his own home, so how could he be rejected then, either?