From a country who strips one's citizenship if one gets another (Japan) and following the court cases to allow dual citizenship I say the motivation for dual citizenship is not because so that they can work for their origin country. Duties and rights of citizen work in both ways.
From what I can tell the main motivation for citizenship is a) directly related restriction in job market ( eg. operating license for the field) or b) to legalize and secure their right to stay with their family members. Immigrants have financially attached to the country of living and their decision is often practical, and their vote is dependent on whether the policy is beneficial to them, like people with single citizenship.
It needs proper background check for sure, but the argument of foreign interference is fear mongering and often xenophobic imo.
Shchedryk (Ukranian original version of Carol of the Bells) comes to mind. Folk rhymes better with their original tongue in general