Why is it impermissible to supplicate for the listener during the Friday sermon if it is done in the heart, while it is permissible for the congregant to supplicate during prayer if the imam reaches a verse containing supplication?

The most proper behavior during the Imam's sermon is to listen attentively and ponder its meanings. It is permissible for the congregant to say "Ameen" to the Imam's supplication, or to invoke blessings upon the Prophet, peace and blessings be upon him, if he is mentioned. It is also prescribed for the worshiper to supplicate when an verse containing a supplication is recited, or to glorify Allah when an verse containing glorification is recited.