Do you think fictional characters have to be likeable?
The main character? Yes.
Other characters? Mostly.
I don’t want to read a novel where I don’t like the main character or characters because I want to send time with characters I like … not characters I don’t like. In a romance, I want to like both the hero and the heroine, because I want to be happy when they end up together.
There are novels I’ve given up on because I didn’t like the main character. In fact, not liking the main character is one of the few reasons I’ll stop reading a novel.
I also want to like the other major characters. If a character isn’t likeable, I want there to be a good reason why they’re not likeable. Perhaps they are the foil for one of the main characters. Perhaps they’re the character who is going to be redeemed by the end of the novel. Perhaps they’re the evildoer (I prefer not to like the antagonist, especially in suspense).