Your argument is still idealist, not materialist, and thus relies on supernatural explanation. Appealing to the idea of a universal human spirit that trends towards imperialism and increasing power is a supernatural explanation for why imperialism exists, and why power structures are formed. Same with the idea thay any "unchecked" ideology will "assert itself unilaterally," which itself could be a good thing!
Imperialism is caused by capitalist expansion, capital expands outward and seeks foreign markets to plunder in order to fight the tendency for the rate of profit to fall. This isn't because of "human nature" or any other vague and supernatural explanation, but because of material processes of economics.
If your arguments are restrained to the realm of the supernatural, we can't take them seriously.