I'm part of the volunteer group (Scenic Streets of Oakland) that tries to maintain the vegetation on the 24 on & off ramp connections to Claremont. The city can't do anything about the encampment on the off-ramp because it's state property under CalTrans control. All CalTrans can legally do is chase them away for a few days. That's what has evolved over the past several months--CalTrans tells them that they must move, they do for a few days, then they come back.
Maybe the Highway Patrol can do more because this is also a troubling safety issue. You're not the first person to mention the safety hazard of pedestrians on the off-ramp. Earlier this month there were 2 SeeClickFix submissions concerning this encampment.

Thank you for your request. According to our system, we already have an open service request of this kind at this location. Your request has been combined with service request #670998. If you would like to check the status of the request, please contact the Public Works Call Center at 510-615-5566 or pwacallcenter@oaklandnet.com. This issue can also be followed by watching http://seeclickfix.com/issues/2842715.