Answer:
Yes, it supports that view because Mexico which is a country in North America did not want Russia, a European country to dominate North America. Therefore, they encouraged the American annexation of California.
Step-by-step explanation:
The excerpt says that the Russians already had Fort Ross in their possession and that they were expanding as seen in their other smaller outpost which extended far into the Farallon Islands. The population was also increasing as the territory expanded. The Mexicans who are North Americans wanted to protect the territory from Russian domination.
For that reason, they encouraged the Anglo-Americans to move into California. So, this annexation of California was actually in the best long term interests of North America.