The planktonic/haploid scuds are separate organisms from sapient scuds. They are effectively a three sex species, male/female/carrier. It’s like if your gametes went out and mated for you, then found another person, gave them some haploid eggs to contribute genes to and gestate, then kicked the bucket. Infant sapient/diploid scuds hatch from the mature eggs and are raised into society the usual way.
Scuds don’t really have the same sex-centric modesty values as other races because they don’t have sex in their large sapient diploid stage. There’s no behavior to shame the kiddies out of doing so they don’t get accidentally knocked up– laying fertile eggs is just something that Happens after puberty, and if you don’t want the offspring you smash the eggs. Cultures that do cover the bits usually do so out of hygienic squeamishness, because waste comes out of the same hole.