The 34-year-old midfielder received the punishment on Wednesday after admitting a Football Association charge.
"Eighteen months seems a long time to me in light of other things I've seen in the sport," said Dyche.
"Eric Cantona was given a nine-month ban for a kung-fu kick."
"We thought there was a chance, of course [of this happening]," added Dyche. "We're not naive. Joey understood that. On the football side of things we didn't want it to get in the way of thinking he was a worthwhile player to bring back. We wanted to get on with it, give him a platform and he's done that."