It is not only BA which is affected. Check the departure bopards and you will see many other airlines unable to fly from LHR. BA is operating most of its services from both LGW and LCY.
It is not only LHR which is affected. Check AMS and FRA and both airports have significant disruptions.
I was affected by the snow, BA got me home. I am flying again this week.
BA and even BAA are not superhuman, these are exceptional circumstances, and you simply have to expect exceptional disruption.
Or would you rather be reversed out of an icy stand only to skid into another aircraft, or be propelled into the air along an icy runway, with iced up wings, to a certain death?
Honestly, I really despair at just what people expect can be done to alleviate the situation.
Sometimes stuff happens beyond human control. UNderstanding that, and adapting to manage the situation makes for a much happier life.