You didn't read the verse. It said "atonement for sins"
The Lord Jesus Christ said "Unless you believe that I am He you will die in your sins"(plural). There is no atonement for sins apart from Christ.
Sirach did not understand that it is the LAW, to Honor your Mother and Father, and that it is SIN not to do so. Honoring your Mother and Father does not ATONE for SINS. Only CHRIST Alone Atones for SINS.
I’ve read it several times, for it has been given to me as a penance in Confession.
Why argue about little things?