The annotation “egg” is not available at the kingdom level for animals (for example: https://www.inaturalist.org/observations/19958006) or sometimes at the phylum level within animals. This issue has been raised a couple of times before: https://forum.inaturalist.org/t/add-annotate-life-stage-egg-to-kingdom-animal/20267, https://forum.inaturalist.org/t/mollusc-lifestage-egg/13203.
The great majority of animals produce eggs, although the eggs hatch internally in placental mammals or (for example) Viviparidae gastropods. Some species reproduce by budding (Porifera) or have alternation of generations (Cnidaria), reproducing with budding or with eggs.
Giving the option to use the “egg” annotation more broadly would allow identifications to be made more precisely. If an annotation is wrong, someone can disagree with it.