All people should disclose whether they submit to Allah or not. Those who are against us are our enemies and must be fought. That includes people who call themselves Muslims but who don't lead their lives as such - people who drink, who don't pray, who don't fast, who have constantly changing partners and who are unable to recite the Koran.
It is one of the great troubles of life that we cannot have any unmixed emotions. There is always something in our enemy that we like, and something in our sweetheart that we dislike.