Counters to any potential arguments against these songs being added:
Young Girl A: Suicide themes are in many songs like Monochrome Blue Sky.
Rabbit Hole: Scared Spear Explosion Boy got into DIVA X. Enough said.
DONUT HOLE: Two (maybe more) GUMI songs have gotten into Project DIVA in the form of vocal edits. The two songs in question are High School Days (with a Miku cover) and Travel to the Other Side of the Moon (with Rin & Len).
I'm very bitter about DIVA X having some amazing songs like Raspberry Monster, Love Trial, Umiyuri Kaiteitan, and Urotander Underhanded Rangers and those songs being exclusive to that game. The only song to be in any of other games (songs in medleys don't count) is The First Sound lmao