"Does that mean the parable of the Good Samaritan was just a joke?"
I've heard of this parable but can't remember the story. Hence, I do not know whether it was a joke. I don't understand what this has to do with what I wrote.
A Jew had fallen among robbers and was beaten within an inch of his life. He's lieing there on the side of the road, dying.
Two Jews walk by and ignore him as they don't want to get involved. A Samaritan (A foreigner, despised by Jews then), comes along and rescues the guy. Takes him to the nearest town, and pays for his care, room ,and board out of his own pocket.
The question Jesus asked was "Who was this guy's neighbor?" The answer was, of course, the Samaritan. The foreigner. The despised, non-person who helped the guy.
Your posting of Jesus meaning that Jews are supposed to love only Jews, etc. is totally disproven with this parable that Jesus Himself told and taught.