Islamic political parties

Recently, the demand for banning the Islamic political parties is getting momentum these days, although this demand was in the political arena for a long time. For the last one year or so, the demand for trial of liberation war criminals came to the peak and now it seems to be dying out. These demands are coming from political parties or their supporters and affiliated bodies. Why are we really demanding an end to religion based politics? We know that all political parties have some ideology and great leaders whom they follow. If this is acceptable to us, why cannot we accept the Islamic political parties which follow the ideology of Islam?
We must acquire enough knowledge about Islam and know our religion in depth before we make any such demand for banning the Islamic political parties, which otherwise have got the same right like other political parties that follow the ideology of some human being.