I've also heard acacia isn't something rabbits should eat. However, kaininhols are so widely used by so many people that I went ahead and bought several anyway. They get chewed, as it's really soft wood, but they don't eat it. I haven't heard anything negative about using hols, but I'd be interested if there have been negative experiences.
I tend to think of it in the same way that carpeting, linoleum, painted/stained wood, etc. is not good for rabbits to eat -- all those things are in my house and get nibbled, and they're definitely not good for rabbits to consume, but that doesn't mean I won't have my rabbits around them. Rather, I just make sure their individual behavior and unique environment aren't cause for concern.
My best advice is to be knowledgeable about your rabbit's surroundings (which you are!), and deal with anything that poses a risk, like if your rabbit *eats* (and swallows) the carpet or drywall or something, rather than just chewing/destrying it.