Hi Mikkel,
"Available" in this context means delivered and supported by SAP.
BADI that you saw in 7.5 was a How To ... Guide showing how to use SQE BADI on example of matrix security. It wasn't a full solution because you have to secure data when it's written back as well.
In 10.1 matrix security is delivered ans supported by SAP and works for Reading data as well as Writing it back.
Regards,
Gersh