I don't think that is a fair comparison.
A dating service serving a niche can help people pre-filter their matches. For example someone of higher education or earning might want to only find people of similar education. It would be discrimination to prevent people of lower education from purchasing from a cup cake delivery service. But not to filter them from a dating service.
As I understand it there are dating services that specialise in matching non straight couples. Is this discrimination against straight people?