I actually thought the same thing at first, however, I am able to tolerate fats just fine. I had eggs and bacon (both gallbladder triggers) earlier and it didn't even phase me. It must be the lactose and by the way, I didn't drink my kefir straight either (it's a bit too strong for my taste buds), but instead I was taking it with whey protein powder which could be why I reacted to it. My reaction was probably from the lactose in the whey powder and not from the kefir. I really should have considered that before but I clearly wasn't thinking of every possibility at the time. Either way, I am still afraid to drink kefir for the time being. I'm still concerned that the kefir may have played a role in the start of my whole issue. I think I'm gonna pick up some Lactaid and then try some dairy again to see if I still react that way which should confirm my suspicion that it's a lactose issue. It's just still so strange to me that I could suddenly become lactose intolerant. I really hope this isn't going to last forever.
Fermentation by the cultures in the kefir should eliminate the lactose. And lactose intolerance is caused from a lack of flora. So that does not make a lot of sense unless the bacteria are not colonizing for some reason. Maybe you need to focus more on prebiotics instead of probiotics.