:salamext:
Yeah i understand where you're comin from, in my opinion you gota actually pull them closer instead of just say that you've got an option, because in reality we don't - its either paradise or hell.
If a person doesn't take the first step to ask them to revert, they may even feel shy so its good to be confident and ask them to actually become one - then it's upto them to take that step or back off kindly.
That lecture is good i feel because it opens a persons mind upto how this world wasn't created by chance, it also explains why islaam is the truth [and it shouldn't just end there] but if someone has actually heard the lecture whole heartedly and they are sincere, they will desire to come forward. Sister Angelzz (from this forum) is an example of this maasha'Allaah.
If we always just act like we not desiring it for them, then it may be a sign that we're not actually sincere, because if we were - we would be afraid for them so that they don't enter hellfire. This is what the prophets would say, they would tell the people that they fear a day when the people wouldn't be able to turn back, and the only way forward would be hellfire [for the disbelievers.] The people would turn their backs and close their ears.
Whereas in our time - thir are people who are trying to find out the purpose of life, so it is our duty to give the message clearly and bring them into the blessing of islaam, instead of just simply making them feel warmer towards it.
That's just my opinion.

So i feel it would be good to use that as dawah material insha'Allaah. And Allaah Almighty knows best.