Why did Matthew Arnold consider Dryden and Pope less than genuine poets?

Matthew Arnold categorized John Dryden and Alexander Pope as less than "genuine" poets because he believed they composed their work in their "wits" rather than "in the soul".1

In his critical framework, Arnold emphasized the necessity of "high seriousness" and the ability of poetry to serve as a profound "criticism of life". Because he felt that Dryden and Pope relied on intellectual cleverness—the "wits"—rather than the deeper, more spiritual or emotional resonance he associated with the soul, he viewed their poetic output as lacking the essential quality of the greatest masters.1