Yes, no one fought for Poland, everyone fought for own interest. So what if Britain and France declared war on Germany if they didn't even attack them or supported Poland in any way? The reason why Britain has declared war on Germany is because Germany has taken too much Influence over Europe, first annexation of Austria then Czechia and invade Poland, do you think Britain could let it go? Britain had to defend an Empire spot where Germany were on the raise and with each year they would only get stronger and stronger, Britian had to prevail and stop them. Poland basically had no side in ww2, it was just patrations of Poland between Germany and Russia, no one fought for us and no one cared about us. For such event we should only blame our leaders and nobody else, they set us in conflict on both fronts.