Alone: separate, apart, isolated from others; solo, without company; exclusively, uniquely; without aid or help. I don't see anywhere in the definitions in the OED, Merriam-Webster, or at Dictionary.com where it says your allies and/or companions have to be capable of winning the war alone. Most of the countries in the Empire declared war within 24 hours to one week after Britain did. The fact we lost tons of materiel and human lives to German submarines suggests rather strongly that, far from being alone, Britain was receiving materiel and soldiers well; before D-Day, The reality is that the partisans and resistance fighters, the colonial soldiers, the other nations also fighting on their fronts were all part of the same anti-Nazi alliance: Britain was emphatically not alone. It simply had the best orator and propagandist at the head of its government.
And, yes, you are right about the majority of Indian deaths being civilian. I admit I have always considered them with the soldiers because so many of them died of starvation when Britain confiscated their food for its own people.
You were born into a highly social species. The basis of human society (and that of many other social species) is co-operation and mutual aid to increase the individual's chance of survival and reproduction, make life for group members easier and, at least since Neanderthals and Denisovians, longer, rather than, as Thomas Hobbes opined "nasty, brutish and short". While it is quite true that there are those who game the system to reap more than their share of the benefits while giving less or nothing back, overall, those who give more are more likely to 'earn' the respect of their fellows and gain the help they need to live as well as possible within whatever circumstances they find themselves.
Don't be too sure that the evil face no consequences. Until their book is finished and closed, you cannot know they will not wish once more to ride down the slope on Rosebud. I knew a woman who was the head nurse on a terminal ward for years -- to this day, I don't know how she did it. She told me one evening that, in all those years, no one had ever died wishing they'd made more money or achieved greater power, but many of the elite that passed through her ward died alone.