Making da'wah (or calling or inviting) Muslims to Islaam is a concept common among almost all Muslims. It does not imply being a part of any particular political viewpoint necessarily.
The group Jamaat ut Tabligh which originated on the Indian subcontinent and is entirely apolitical focuses 99% of its attention on making da'wah to Muslims.
This phenomenon is also present among Jews and all variety of Christians.
Someone may be a Muslim simply because they grew up in a Muslim family or a Muslim country and they may know little about or practice little their faith. Thus they would have to be invited to Islaam.
And all of us have things we don't know or things we don't practice and therefore we are all in need of being invited to complete submission. This is a lifelong process.
Again, the above concepts are common to Muslims across the spectrum of beliefs with regard to politics.
While Qutb may have been especially blunt about this idea in other contexts, in this context I don't think he was saying anything unusual at all.
And Allaah knows best.