I don't understand the meaning of this "homosexual subtext"

[intra_linear]

Itsuki: I was just jealous of the invisible bond of trust between you and Suzumiya-san.

Kyon: What are you talking about?

Itsuki: Why her? We could have a bond of trust. It could be visible. Why not me?

Kyon: What?

Itsuki: Uh... CLOSED SPACE!