If you read other manufacturers sites they will tell you not to use shave oil and not to use swirling motions with a brush. Probably about as valid as some of the instructions packed with TI Razors.
I have one Thater and I pretty much exclusively face lather and have never had any issues with it or any other brush for that matter.
They probably figure the more you treat their product with kid gloves the less issues they will have dealing with you down the road. Hedging their bets I would say.