Lore. Siege comes from a time where mobas, online shooters and other multiplayer games were big on building a “universe”. Every single one of the operators had full bios, and some also had videos about them. They also had videos explaining in-universe events, such as the alien virus that introduced the two agents from CBRN (Chemical, Biological, Radiological and Nuclear Threat Unit), Finka and Lion, and had an entire special pve game mode made for it, that eventually became its own spin-off game.

It’s a holdover from the early days of Rainbow Six would be my guess. You had like a dozen or so operatives with mild differentiations in stats and traits. Each guy had a “service record” of sorts, which gave a little more context for what was, in essence, the games’ lives system. If I remember right, some of these names were either pulled from or incorporated into the Tom Clancy Universe of novels and adaptations. It was a practically free way to inject some story and character into games that were pretty light on those details otherwise.

Of course, modern Rainbow Six has no need for these things, but inertia is a bitch, and you can be sure some grognards would piss and moan about a “feature” being removed if they stopped including these details.

Lore maybe?

There are often a lot of communities that love reading into the lore of characters, even shooters. Overwatch is a good example of this.

There is a bunch of lore for the characters, and lore for world events. Some years ago they even made an entire animated series with 5 or 6 short videos explaining how the Rainbow 6 team changed directors. There are explanations for the game modes, and also for the enemy factions that show up in the pve modes. Back when I played, most players knew quite a bit about the lore and the characters.

They should apologize for their insensitivity