The reason Su Yu is exposing the situation at Grela-13 is, of course, a decision made after discussing with the hymn.
These are actually two different paths.
One is the aggressive route, and the other is the conservative route.
Previously, they wanted to take the conservative route.
By not exposing information about Grela-13, the intelligent machines would be unaware of the situation there, and sending spacecraft for exploration might take decades to determine that Grela-13 has already fallen.
But the downside of the conservative route is:
First, Lea and No. 3 cannot appear publicly;
Secondly, information about Grela-13 cannot be disclosed to the Holy Silver Man.
These two shortcomings would delay Su Yu's speed in enhancing his strength.
After discussion, Su Yu and the hymn decided to take a more bold path, the so-called "aggressive route."
By taking the aggressive route, they would openly display Lea and No. 3 from the beginning.