[inglor_cz]

An ejection seat is basically a rather powerful small rocket with huge acceleration - much more forceful than what astronauts nowadays experience. Human bodies aren't built for riding such rockets. Injuries from ejections are pretty common and some of the ejectees are never fit to be combat pilots again.

[krisoft]

Yes, ejections are violent. Can cause injury, can cause death. No question about that.

Spinal injuries are likely and ejections frequently end the flying career of pilots for medical reasons.

What does this have to do with the claim in question?

They claimed “people who survive flight ejections and hitting water at high speed tend to have had their spleens removed”

This implies that if you look at the group of people who survived a flight ejection (over water and hit the water at high speed) you would find that most have no spleen. Do you find this plausible?

[inglor_cz]

A trauma surgeon would be a better fit to answer that question, but crushed spleens seem to be common in high speed impacts (car crashes, falls from ladders etc.), at least as far as I can judge it from my limited circle of friends who have had such experience.