According to the Torah (and let's forget the Rabbis for the moment) there are certain things that one should (and shouldn't) do!
These beliefs are central to Judaism and, in my opinion, are what has allowed it to continue to survive all those that would have destroyed it.
To discard certain aspects, as not being relevant, is to pick and choose from what many consider to be divine, and who gave us that right?
Does one choose what parts of a car one wishes to use?
Would one fly in a plane where that pilot decides he can do without one of the engines?
Will an e-mail arrive at it's destination if you substitute a comma for a full stop?
The reform movement was started (strongly) in Germany just before the war, by people that wanted to be seen as less different from the general population.
They threw out what wasn't relevant and substituted for other things, have you ever seen a Chanuka bush? The tree is totally pagan in origin and has NOTHING to do with Chanuka at all!
Jews became assimilated very quickly and it was difficult to tell them apart from the Germans> However, that did not stop Adolf shit-ler from killing them!
So when you say ALL JEWS, who do you really mean, those that try to follow what is written in the Torah, who consider it to be divine (after all, Judaism is a religion, and therefor, divine in origin) OR, those that pick and choose and therefor negate the inherent divinity by saying (through their actions) that the Torah is not divine?