Earlier quoted context omitted.
This is as discriminatory as choosing strawberry ice cream over chocolate. To say, not at all.
What is your justification for that? If an employer did the same thing, would you argue that's also not discriminatory? Or, to pick a notorious example, if a cake shop only agreed to sell to straight couples, would that be the same? If not, why not?
In your cake shop example, the more accurate version would be some gay couples only agreeing to buy wedding cakes from cake shops with gay bakers.
On account of it's the customer choosing the service provider, albeit with the help of filters provided by an aggregator, instead of service providers denying service to customers based on their belonging to a class.
edit: I missed that you can, as a woman driver, also filter out male riders.