Actually people are often forced to convert, even against their will. In early muslim history, the bebers and Iberians were forced against their will to either follow Islam or die in the slaughter of the armies as they continue their march into Europe.
I am not here to refute and debate, but it seems that you are mistaken in saying the above lines. Please go through what is said here: http://www.islamicboard.com/refutati...tml#post638653
Muslims have never forced anyone to Islam. And its of no use if one is forced to proclaim the Shahadah because its Imaan thats to be entered into the heart and that cannot happen unless one proclaims the Shahadah out of his own free will. If a person says Shahadah due to external pressure, then we can't say if Imaan has entered his heart or not.
There are more chances of a person becoming a Munafiq if he is forced to Islam and Munafiqeen will be in the lowest level of Jahannum. So increasing the number of Muslims is not what is required, but practicing Muslims are required.
So Islam is always presented first before asking anyone to enter it.
Its Allah Alone who turns the hearts.