It's a personal and business decision. Just like any other professional, therapists make decisions about their work hours based on both their personal needs and on what works best for their business. Some therapists may be okay working every evening if they don't have families to go home to. Others may offer one or two evening or weekend hours a week. Others prefer to keep regular work hours to perhaps match the hours of their spouse or families. It sounds like there are a number of therapists who do have alternate hours available, and you have to look to find one that works well for your own schedule. I don't find a choice to keep regular work hours "obnoxious" though, just a business preference.