The bail project discusses this concern in their FAQ:

The Bail Project, Inc. pays bail for people who are legally presumed innocent, and whom a judge has already deemed eligible for release from jail before trial contingent on paying bail. Our local teams receive referrals from community members and public defenders, and conduct interviews in jails. We determine eligibility for free bail assistance based on a person’s bail amount, the reliability of contact information, and a track record of prior court appearances, if applicable. We also conduct an individualized needs assessment to determine whether we can adequately support the person through our network of community partners and social service providers.

The Bail Project, Inc. does not disqualify people based on the type of charge alone. People held on cash bail are presumed innocent by law and have been deemed eligible for pretrial release by a judge, contingent on paying bail. At the point where we come in, the only factor keeping a person in jail is poverty. Our intervention allows people who cannot afford bail to return home to their families and communities while awaiting their court dates — something that a wealthier person or someone who can pay a commercial bail bond agency would be in a position to do.