If your users are from poor countries, you'll also get pennies from ads. TAANSFL. If you have an actual community, it's more efficient to simply ask for donations.
People from wealthy countries usually forget about the rest of the world, when they talk about things that annoy them.
That said, if you're running a hobby site that only targets people from a poor country, the money has to come from them anyway, be it from ads or from donations. In that particular situation, why would ads bring more money than donations compared to sites targeting people from richer countries?