"But I do know people that have stalkers and it's not nice"

This quote by Daniel Craig speaks to the reality of the circumstance of having a stalker. It is clear that he has some understanding of the issue, either through individual experience or through individuals he knows. He is stressing that having a stalker is not a pleasant experience. It is most likely that he is attempting to raise awareness of the problem and to motivate people to take steps to protect themselves from possible stalkers. He is also most likely attempting to highlight the importance of taking stalking seriously and not brushing it off as something that is not a big offer. It is clear that he is attempting to make a point that having a stalker is not something to be taken lightly which it can have severe effects.