Suppose your sister’s husband and in-laws would beat and abuse her. With difficulty she managed to escape their clutches. Could you now happily live among her ex-husband and in-laws and mix with them comfortably? You could not claim to love your sister if you were friends with those who abused her.
Allah’s love for us is a million fold the love any of our dear ones have for us or we for them. The non-Muslims are unjust towards Allah (subhana wa ta’ala) for they refuse to recognize His rights. This Hadith states that if we are comfortable with Allah’s enemies, living and mixing with them, then it means that we are like them.