I would assume this was a Dash 8, so I really can't comment on their procedures. I know we will usually move mountains to accommodate any type of service animals on mainline. A couple years ago we had to IDB 2 passengers and rearrange lots of people to make room for a woman's 2 HUGE ESA's. the only place they would fit on the floor was the bulkhead and there was no space for anyone to occupy the other seats.
Recently there was another story about a vet that was deplaned because he refused to put his service animal under the seats. The GA had rearranged people on that flight as well to give him an empty seat next to him and more floor space but apparently the passenger wanted the big dog to occupy the now empty seat. Unfortunately that's a big no no. Service animals are allowed to sit in your lap if they're no larger than a lap child and a golden retriever or full size lab don't meet that requirement.
I look forward to hearing the full story from both sides of the fence on this one.