Hate is not necessarily justified by a reason, but it always has a reason. Most likely, anyone who claims to hate with no reason is unable to identify the reason, but the reason still exists. Probably the most overlooked reason for hate is having a prejudice against an attribute of the person. These attributes can range from race, gender, apparel, age, and voice. These attributes don't justify hate, but they are commonly the starting point for disliking someone. obviously, their actual behavior causes hate too. When their behavior causes hate, it's
very easy to identify the reason.
I am not sure if love requires a reason or not, but I don't think the answer affects whether or not hatred requires a reason. Similar to hatred, I think love can be caused by a combination their attributes and behavior.
because of my Christian background, I...
have a hard time believing that love can't be unconditional. If the bible is true, then God loves us without any condition. Most likely, God is capable of unconditional love, but people need a reason to love