Even the page you link says the same:
This was a result of a rapid escalation starting on 24 August 1940, when night bombers aiming for RAF airfields drifted off course and accidentally destroyed several London homes, killing civilians, combined with Churchill's immediate response of bombing Berlin.
Obviously the bombing of Berlin has nothing to do, really, with the accidental and patently unintentional off-mark fall of some bombs directed to a RAF airport during a nocturne bombing raid. Besides, bombings take days (or weeks) to plan and execute. The Berlin bombing was probably planned in advance and would have been executed in any case. The off-mark German bombs were taken as an excuse in front of history, public opinion etc.
If you have an Encyclopaedia Americana at home or at your local library you find a very nice "Battle of Britain" article stating the point of view that I expressed above.
History it's history. Don't take it as a religion. Re-examination of history past is the only way to avoid falling into the same mistakes in the future.
Relax. If you don't declare war to them anymore, they won't bomb you anymore