According to Leitzmann et al 2004 the average number of male ejaculations in lifetime is approximately 8700 times. That would be 26,1 litres of cum per male.
Edit: 2047 male ancestors would have produced roughly 53 427 litres of cum. Do we have data on energy density of cum?
The source you provided states 3324 children have died and another 1000 missing since Oct 7. Not "3000 killed every day", as you claimed.
Those numbers are still horrifying, but should not be used to belittle cruelty of terrorism. Whataboutism is futile.