That's only true if the service is likely to induce behavior that require such intervention - otherwise it's absolutely ok, for example, to call a public ambulance when a taxi customer gets sick, as oposed to arranging private insurance for your customers.
There is no proof ridesharing would induce criminality, quite the contrary, it's a much safer alternative to random hitchhiking.
If you shift a large enough volume of traffic into that mode of transportation and externalize 'support' to emergency services then you are taking a free ride on a scarce resource. At a minimum there should be a first tier of support within the company offering the service, if only to serve as a mechanism to immediately halt providing the service to or from that particular passenger or driver until the matter has been dealt with.