1. The responsible person will be automatically allocated as resource to the activity. For us this is not really necessary because as you set the person as the responsible person thereby he/she can see the activity. So he/she is quasi allocated to the activities twice. For us the responsible person doesn’t always have to work on the activity. Do we see this wrong? Can you explain me why this happens?

This automation does not seem to bother most users.
It does not seem weird.
But this automation could be disabled through parameter : tivcket #3052 recorded

2. If our planer makes something on a project or activity she will be allocated to the project automatically. But she is already allocated to the administrative project, so she doesn’t need to be allocated to every single project. Also if she deletes herself at a project she will be allocated again if she makes something on the project. Is this right? Does she have to be allocated to every single project?

There is no automatic allocation to project.
There is automatic assignment to activities of administrative projects, and this is required to respect ProjeQtOr design.