This is for security reasons, since it will take some extra effort to make additional rules this way. Now, for example, if you want to have support for the LOG, REJECT and MASQUERADE targets and don't have this compiled statically into your kernel, we load these modules as follows:
Así, si por ejemplo quieres tener soporte para los objetivos LOG, REJECT y MASQUERADE y no los tienes compilados estáticamente en el núcleo, deberás cargar los módulos como sigue: