the flanders joke was that it's very hard (stupid, frankly) to love your neighbours, when your neighbours are people like the simpsons. but, the buffoon tries, anyways. it was a deep caricature of christianity.

a rational flanders would have built a moat between the properties, or moved away, or bombed them, or something - for the good of humanity. but, because he's a christian, he insisted on loving and forgiving and accepting them. and, that's the joke - it's about how stupid christianity is, because it would preach acceptance rather than seek to protect itself from obvious harm.

you're not supposed to identify with these people; it's satire, and they're literally cartoon characters.