Add to it that announcing one's AoD aloud is probably giving your enemy, or even your temporary allies, the perfect tool with which to bend you over the table and fuck you up the butt without warning?
Yeah, no, not something most quasi-sane Hollow breeds are going to openly talk about. To do so with another is either a sign that they're dangerously broken, have no fucks left to give and are near suicidal, or they genuinely bonded to and believe whoever they're telling is trustworthy enough not to use said information against them.
I can't speak for the collective- Neither Ira the character nor Boss the player have spent a lot of time interacting with other Arrancar players/characters. For myself though.....
I quasi agree with Garra's point of view that Aspects aren't a thing that everybody should just know about and understand, but then circumstances arise. In Ira's case, it's pretty goddamn obvious that he's got something going on. Something about being pissy about something being a natural state for him. Even at his calmest he's got a little bit of simmering resentment. And just looking around it would be immediately obvious that other people are capable of expressing emotion other than 'ALWAYS ANGRY ALL THE TIME'.
It's actually a thing he's vaguely interested in, and 'researches' (nothing he does investigatively could be considered professional or serious) it in his spare time. Why are so many of his fellow soul-eating abominations so goddamn chipper all the time?
And in his case, he actually has someone kind of like him (Atrum) he can actually make direct comparisons to and such. Which is why there is/going to be so many deliberate parallels between them.
To be fair though, Ira's about as unsubtle as you can possibly get.
Seireitei is crumbling and the Gotei is a shell of its former self. Ravaged by the plague, the surviving Shinigami struggle to maintain the balance, but with so few of them left, the work is taxing and their fortress-city has fallen to neglect. Spread thin across all fronts, their diminished presence has been noted by friend and foe alike.
The Arrancar have rebuilt Las Noches and are rallying. The throne remains empty, but self-styled Espada have risen up from among them and are vying for control, each one endlessly testing the others’ weaknesses. Too evenly matched for any one of them to claim the crown, they bide their time, waiting for the opportune moment.
On Earth, all seems well—but there is a war being fought in the shadows as the mortals find themselves lacking the protection they once had and so sorely need. The Quincy, having realized the oppressive specter of the Shinigami is no more, are flourishing, and are fighting the Hollow-breeds with renewed vigor.