Worm
Taste the diffidence
I would be more intrigued if there was a more direct influence, that hasn't been extracted or manipulated by other artists. "The swinging guitar" influence is inevitable, but there is no distinctive groove to the Smiths and ironically the Velvet Underground is known for its lack of R&B influences in their sound. The likelihood of the Smiths or Morrissey being directly influenced by R&B is small though.
Influence is rarely that direct.
Anyway, Johnny Marr has said many times that one of his inspirations in The Smiths was Bo Diddley. If Marr was a fan of Diddley and other R&B artists, and was listening to them quite a bit during his days in The Smiths, then one way or another there is an R&B influence on The Smiths. As Marr said in 1997, about "How Soon Is Now", "I arrived at the studio with a demo of the whole thing, apart from the tremolo effect--though that was bound to surface on a Smiths track sooner or later, 'cos at that time I was playing Bo Diddley stuff everywhere I went". I don't know how influence gets more direct than that, unless you define "influence" as "sounding alike", which is too narrow. Perhaps Bono hears the "influence" because he understands how artists borrow from their inspirations, in which case I would use his definition.