It’s not about rank or age. It’s about who’s been present at the last battle of the War of the Last Alliance. Also, at the time of the depicted scene Elrond never was in Valinor, so at this point in time Gandalf definitely easier Elrond’s senior by orders of magnitude.
This text feels like an insulting compliment. Or a complimenting insult. Or something. It absolutely swings backs and forth between toxic masculinity and comfortable inclusivity.