Is it possible to love all people unconditionally?
I do not speak of love as falling in love with an other human being. But to not be able to hold any hate toward anyone ?
Arnold Schwarzenegger tried to do that (love everyone). In fact, the maid's son is the spitting image of him.
True love doesn't involve just satisfying lust (though those in love satisfy every aspect of their lives with each other). The caring that we have for all of society is very special.
I see kids come out of a Catholic church, then toss candy wrappers on the ground. Sure, it's pollution, but it is an even worse type of pollution....pollution of the soul. It means that they don't care enough about other people to keep the world a tidy place.
To hate is to judge.
"Judge not, lest ye be judged" (Jesus, Sermon on the Mount).
Yet, if we don't judge God and Jesus, we would not judge them to be good and wholesome. If we don't judge the devil, we won't recognize him. If we don't judge someone who is "fightin' evil" we might mistake them for a righteous man, rather than a tool of the devil who makes wars against innocent nations.
We, therefore, have to judge, in our own hearts, but just not bad-mouth others publicly. For example, when President W. Bush called various Iraqis names (Dr. Evil, Dr. Death, et al) he motivated wars against them, and that killed perhaps a million innocent Iraqi people (some were innocent women and children). Of course, that also involved "bearing false witness" (taboo under the 10 commandments).
If we don't judge others, we follow them, and that harms others (it is sinning).
The ability not to hate someone is also the ability to ignore their crimes, and to aid and abet them in further crimes.