Is it wrong to forbid someone who steps over people's heads in Friday prayer and asks for a place by gesturing, and to ask him to go back? And is gesturing considered idle talk during Friday prayer?

It is not permissible to step over people's necks on Friday after the Imam has sat on the pulpit, due to the harm and idle talk involved, which are forbidden. Abdullah bin Busr narrated that the Prophet (peace be upon him) said to a person who was stepping over people's necks: "Sit down, for you have caused harm." Stepping over necks is worse than touching pebbles, which is forbidden, and anything that distracts from listening to the sermon is unlawful. Therefore, seek Allah's forgiveness and do not repeat such an act. Your prayer is valid, Allah willing.