﴿ إِن كُلٌّ إِلَّا كَذَّبَ ٱلرُّسُلَ فَحَقَّ عِقَابِ ﴾

“not one [was there] but gave the lie to the apostles - and thereupon My retribution fell due.”

Each one of the factions did not but deny the messengers for when they deny one they have in effect denied them all since their call to God is the same one namely the call to affirmation of His Oneness. So My retribution was justified it was necessary.