"No-one is brought up intersex or genderless; even though 2% of the population is neither biologically male or female."
Well that one is wrong for a start. Those with disorders of sexual development, even if they don't have the normal combination of sex chromosomes, are all biologically either male or female. What you are doing here is confusing the appearance of genitals with a person's genetic sex.
www.ncbi.nlm.nih.gov/pmc/articles/PMC5866176/
Table 1
Classification of Disorders of Sex Development Associated with Ambiguous Genitalia
XX, DSD
Androgen-induced
Virilizing Congenital Adrenal Hyperplasias
Placental Aromatase Deficiency
Glucocorticoid Receptor Mutation
Maternal androgen secreting Tumor
Virilizing luteoma of Pregnancy
Androgen Exposure (Norethindrone, Ethisterone, Norethynodrel,
Medroxyprogesterone, Danazol)
Ovotesticular Disorders
XY DSD
Impaired Testosterone Synthesis
Leydig cell agenesis
LH/HCG receptor (LHCGR) mutations
Congenital lipoid adrenal hyperplasia (StAR)
Cholesterol side chain cleavage mutations (CYP11A1)
3β-hydroxysteroid dehydrogenase type 2 (HSD3B2) mutations
17α-hydroxylase/17,20 lyase (CYP17A1) mutations
P450 oxidoreductase (POR) mutations
Smith-Lemli-Opitz (DHCR7) mutations
17β-hydroxysteroid dehydrogenase type 3 (HSD17B3) mutations
5α-reductase type 2 (SRD5A2) mutations
Cytochrome b5 (CYB5A)
3α- hydroxysteroid dehydrogenase deficiency (AKR1C2 and AKR1C3)
Denys-Drash syndrome (WT1)
Sex Chromosome DSD
Turner Syndrome
Klinefelter Syndrome
Mosaicism, e.g. 45,X/46,XY
Triple XXX Syndrome
XXYY Syndrome
XX or XY Disorder of Gonadal Development
Complete gonadal dysgenesis
Partial gonadal dysgenesis Gonadal regression
Ovotesticular DSD
XY Persistent Mullerian Duct Syndrome
Low AMH (AMH)
Normal or High AMH (AMHR2)
Malformation Syndrome
CHARGE syndrome
Hand-foot-genital syndrome
MRKH Syndrome
MURCS Association
McKusick-Kaufman Syndrome
Aphallia
Cloacal/Bladder Exstrophy
Isolated Hypospadias
Penoscrotal Transposition
But back to the CIS issue. It's another neologism that's only used to back up a political point. Would you refer to someone as "Cis Black" Which, given the well publicised instances of people identifying as black even though they are white, should be just as relevant to use? And yet it's offensive isn't it? Why is that do you think?