While it is true that capitalism tends towards imperialism, it doesn't mean that all capitalist nations are imperialist automatically. Imperialism requires a developed M->M' circuit (finance capitalism) which necessitates the export of investments abroad to maintain rate of profit, which is why it is the final stage of capitalism. Only Western nations have achieved this, just take a look at where the biggest asset management firms are located (London, New York). Saying that all capitalist nations are imperialist is akin to saying that all socialist nations have already reached communism. That is just not how stages of development work.