What?
That’s based on the incorrect premise that the Liturgy of the Hours is a clerical prayer. Vatican II was absolutely clear: it’s the prayer of the whole people of God, according to their state: ordained, religious, and lay. The Church’s mind is that while it BINDS clerics and religious to the Office, it warmly recommends it to the laity, be it in common among themselves or individually.
The Office has never been exclusive to the clerics and religious. It only came to that because of the exclusive use of Latin and its length. Its simplification and official approval in the vernacular is a great gift to the laity because it becomes their prayer too. Or rather, once again.
Laity praying the Office are exercising their common priesthood as as baptized Christians, while priests exercise their office as ordained ministers and pray in the name of the Church. Either way, it is a participation in the liturgical prayer of the Church.