Intersex is science/biology
Gender is sociology
Intersex is an empirically verifiable thing
Gender is a made up concept, but bolted onto an empirical phenomenon (biological sex) in order to subjugate and control members of the sex that are perceived to be inferior and merely vessels for the reproductive, sexual and caring labours for the male members of the species.
Questioning intersex is anti-science; but scepticism of gender, and the possibility that one may "trans" one's gender is essential in order to liberate women from an oppressive social structure that keeps them under male domination and hierarchy.
At a general level, transwomen can absolutely be valued friends, family members, employees, public servants etc. But they can never do the essential work pertaining to carrying and birthing the next generation of society... which are the crux issues in feminism... bodily autonomy, contraception, termination, breast feeding issues, maternity rights in employment - issues with an immutable materialist biological basis... not the fluffy sparkly stuff like shoes, make up, skirts etc - which are volitional cultural based choices.