Trans people already have rights. Gender reassignment is a protected characteristic in law, they have a right to medical treatment and to not be discriminated against for being trans.
WRT the erasure of biological sex the most pernicious thought is that although biolgocial differences may exist, they do not
matter. That anyone can be a woman no matter their reproductive system. Feminists patently disagree with this.
A Lib Dem politician recently said that parliament could be said to be equal if it were 50% men and 50% trans women. No biological women at all. No women to discuss the realities of maternity policies, of maternal and female healthcare, of childcare funding. This is what the erasure of women looks like.
This SNP politician today said that trans women are "female". What use is the word female if it no longer means "the sex of any species that can produce ova that are fertilised by male sperm"?