What is the ruling on one who downloads lectures from the Internet, then records them and distributes them to young people to spread the Da'wah? And is this action considered an infringement on the rights of others?

It is permissible to download recorded lectures from websites that allow it and distribute them, as this constitutes an invitation to Allah. The Prophet, peace and blessings be upon him, said: "Whoever calls to guidance will have a reward like that of those who follow him, without diminishing their rewards in the slightest."

As for websites that do not permit downloading, it is not permissible to resort to tricks to download material from them, because that is an infringement upon the intellectual property rights of their owners, which are guaranteed by Islamic law, as stated in the resolution of the Islamic Fiqh Academy.