I believe what they are referring to is that it's not any individuals responsibility to ensure that any other individuals knowledge of their marginalization is complete. That's not saying that individuals can't do it, nor that they shouldn't call attention to specific issues as effect them at that time. It's saying that they are not responsible to do the work of teaching someone that which they should learn themselves once the issue has been raised. To do otherwise often feels like the person has to justify their existence and struggles to anyone who asks. That's an unreasonable load for the marginalized person to carry.
So not blame, just where the burthen of learning falls once an issue comes up.
What this is talking about would be if I were to now ask you questions about your marginalization and demanded answers. But since that is not relevant to our discussion here and because it's not your job to ensure that I am informed on any issues relating to your marginalization I wouldn't ask the questions in the first place. You shouldn't have to feel like you have to justify your existence to anybody who possess by and is curious.
People sometimes treat visible members of marginalized groups like they are information dispensers. That just because they are viable they are responsible for entertaining their curiousity. In specific instances where it's relevant and invited a discussion of their marginalization is fine. But it's is not the job of someone to ensure any person interested is told about whatever they want to ask.