The issue here is that there is not great data to support just how much damage you do by charging the batteries cold. The paper linked above suggests that at room temperature (15oC) the LiFePO4 batteries they were testing would provide ~9000 cycles at 20% DOD with a charge/discharge rate of 0.5C. For the same experiment at -30oC it was around 3-5000 cycles. Even at a charge of 1C and discharge of 6C(!) to 50% DOD they still saw ~1000 cycles at -30oC. Yes, the performance is degraded by operating at very low temperatures and relatively high charge/discharge rates.
However, for the use that most of us have, a few tens of low temperature charge cycles per year won't make much difference. If you are a telco running batteries at a repeater site in Tuk, then it would be an issue.
The bigger issue for heavy duty use (eg electric vehicles) is the decrease in capacity - the batteries were really unable to even provide even 50% capacity at -30C.
