Male discrimination in most cases is nothing compared to the discrimination towards women. The example you have given is actually very weak,
as there are plenty of places which are seen as acceptable to have a gender discrimination (notably in favour of men), and notice that the hotel
does not actually deny men custom, only restricts access to certain areas. Also just as additional titbit concerning the managers argument,
some of the night clubs in the city I live have unisex toilets because gender specific toilets are discriminatory to transsexual people.