I sorta agree with you, but I think it's better to keep that to individuals and specific occurances, but still suspend disbelief ICly when it comes to the idea in a more universal sense.
For instance, if someone says, "I shot down 30 battleships today", that's okay, and we should accept that.
But people probably shouldn't say stuff like, "Capsuleers kill hundreds of billions of people for the Empires every day", and individuals shouldn't say, "I've killed a total of 8000 battleships this month", because that breaks the setting, even though it might be true. We should dismiss impossible trends, but not individually anomalous experiences.
The only time I see those two things come up is either bragging or reminding someone that playing an altruistic/innocent capsuleer is nearly impossible to do if you enter combat. The former is as pathetic as any kind of bragging and easily ignored - either A) yes, they did kill that many but so did every other PvE character and it is not something to brag about, or B) no they did not and they are idiots. Both make the claim meaningless and idiotic.
The latter option is the most contentious, because braggart characters are as easy to ignore and laugh at ICly as braggart players are OOCly. For the innocent thing, well, given what we know about crew - if your character does combat you have killed at minimum thousands. The moral contextuality of that killing can be manipulated in any way your character wishes, same as any other morality.
The only other time I see this sort of issue come up is when people discuss the universe itself. Whether it is millions or billions killed by capsuleers on a regular basis, the EVE universe worships death and always has. There is nothing special about that. The specific number is meaningless from my perspective. Does that sort of detail promote a general meaninglessness to the IC universe itself? Of course, but only because that killing has no real impact on the universe. It will always be a relatively static universe where the killing on behalf of empires does not actually have an impact on the state of said universe. So, in my opinion, it is not the absurd number of deaths that is bothersome - it is that those deaths do not have and never will have an impact on the cluster that is bothersome.
There's a reason why so many characters and/or players end up with a weird EVE-form of ennui. All of these actions are taken without meaningful impact or relevancy. But as far as IC interactions go where you run into folks that discuss these details from the character perspective, it is very easy to ignore and avoid. When in doubt, walk away.
@Kat, of course you can ignore it. Either literally by avoiding them or ending the conversation (datapad beeps), or by having your character literally tell them are wrong. They start OOC linking to try to force you, you say you disregard those numbers for reasons X, Y, and Z. Either you move on or you get ridiculed. Either way, problem solved.