I'm trying to answer your question. Choosing who to list on a jobs website is not a hiring decision. The candidate does not work for Jopwell. Jopwell cannot fire them nor pay them anything. Hiring law does not apply to a recruiter, except for their own hiring decisions for their staff.
Thus, bringing up hiring law, which applies to employers, as an objection to this sourcing service is irrelevant.
However they are still doing business with candidates and it is well established that e.g. a restaurant cannot refuse customers based on race. Uber could not refuse drivers based on race, even if drivers are (theoretically) independent contractors and not employees.
This is outside my knowledge of law but my spidey sense is that they are not clearly on solid legal footing.
Fair enough, so your question is one of equal accommodation and not hiring. What this boils down to is how they implement their signup and sourcing process, which is something you're absolutely right that they'll need to do properly.
P.S. I grew up in central CA and had a lot of Hmong, Mien, and Lao friends in school.
Thus, bringing up hiring law, which applies to employers, as an objection to this sourcing service is irrelevant.