Many people are satisfied. It would a little clearer as: sono in molti ad essere accontentati.

the verb " accontentare" means literally " to make someone / yourself content". You can translate this adjective in English with " content" or "happy". Accontentarsi and essere accontentati have different meanings : Lucy contented herself with a cup of tea ( Lucia si accontentò di una tazza di tè) , Many children were pleased to take a pic with NBA star Kobe Bryant ( Molti bambini furono accontentati ( nel loro desiderio) di scattare una foto con la stella NBA Kobe Bryant).