I think it would be a good idea to try a forum which was focused on single/solo travel. For example, if someone found a tour or cruise operator that was particularly good (and priced accordingly) for someone travelling alone, they could share that. Also, if someone had a bad experience at a particular place because they were travelling alone (for example if a restaurant frowned on or delayed in seating a single patron), that would be useful information.

Realistically, I suspect volume on such a forum might be low.

Whether it might also be used to find a travel partner or group, I don't have an opinion. But I agree that it would not be a good use of resources to create a dating service.