I think it is relevant because of the brilliant use of satire and comedy to send up the sillier elements of our society.

Americans are not much interested in political, economic, social or religious commentary, unless it comes in humorous form. This show sends up the pompous, selfish, and hypocritical: wherever they hide. It makes a working class hero of the simple, deeply-flawed everyman, Homer.
The painless, but biting criticism of the show makes me think.
My favorite episode is the one where Bart is sent to Catholic school.

He and Homer really get into the old religion with all its symbols and customs, but Marge remains ever-faithful to her local church: the Western Branch of the Presboluthertarians.

Inevitably, a big fight ensues, but Bart brings them all together:

“We have got to stop fighting like this. We all believe in mostly the same things.
Our stupid differences are trivial in comparison to our stupid similarities"

Perfect!