All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
This verse clarifies that the Bedouins are (in general) more denying of the Oneness of Allaah and act more hypocritically than city people. This is due to their roughness and because they do not interact with righteous people oftenly. Because of this, they are in general more hard-hearted and less knowledgeable about the rights of Allaah than other people.
However, it should be mentioned that the Bedouins are not all likewise, rather; there are amongst them righteous people who do good as in the Saying of Allaah (what means): {But among the Bedouins are some who believe in Allaah and the Last Day and consider what they spend as means of nearness to Allaah and of [obtaining] invocations of the Messenger. Unquestionably, it is a means of nearness for them.}[Quran 9:99]
This is evidence that the verse which you mentioned in the question refers to some of the Bedouins and not to all of them.
Allaah Knows best.