Always_Ask_Questions,
“The question is not only whether something is sustainable [Cuban economy is sustainable], but whether this is a good thing for a Jew to do.”
Good thing there are many rabbis and poskim who are aware of how frum Jews live and who advise Jewish families.
“I am not sure what are the classical sources for using non-Jewish, or Jewish, government funds dedicated to support of poor by people who are able to work, while there are sources condemning it (make your Shabbat k’hol, but do ot rely on tzedokah)”
Do you count the taxes you pay as maaser?