I don't doubt that charity can be useful in some cases however, from what I've read I am not fully convinced that it helps most of the time. I lived in Kenya for a short while several years ago and since then have become interested in African development.
I have read or heard of a number of cases where "do-gooders" only make the situation worse.
For example, after the genocide in Rwanda, the UN set up refugee camps in neighboring Congo to help the refugees. Unfortunately, the refugee camps mainly ended up helping the people who were responsible for killings. They would take refuge there, control the food supply and then use their power to keep on terrorizing people.
Many charity projects are also extremely tough to know if they will work. An example is a story I heard about an aid project in a small village in a developing country. The project's goal was to install a well for the village to use as people (mainly women) would need to walk 2 hours each way every day to the nearest water supply. The project was well thought out and created a sense of ownership amongst the local people. After a number of weeks, the well was completed and there was a big celebration. Several weeks later, the aid organization came back to do a follow up. To their shock, they found that the women were still walking miles each day to get water rather than using the well. When they asked the women why they were doing this, the women responded "We used the well for a few days but then we realised that walking to get water was the only time during the day for us women to bond and talk amongst ourselves."
Another example is that when malaria nets are given away only a small percentage of the nets will actually be used. However, if people in a village are educated about the benefits of malaria nets and then given the opportunity to buy a net for $1, even if $1 might be a day's pay, the nets have a remarkable high-use rate. People are similar no matter where you go - if you get something for free, you value it less than if you have to make a decision with your earnings. You may say that is a good case of charity but if they are selling the nets, it sounds more like a business rather than charity.
A lot of aid sent to developing countries is siphoned off by bureaucrats and government officials thereby making them more rich and powerful and less accountable to their own people. If a government is getting a substantial sum of money from foreign donors, accountability then goes to those foreign donors, not the people of the country.
Over $1 trillion dollars in aid has been distributed to African countries in the past half century or so and what is the result of that? Are many places really better off because of that charity?
Mobile phones are completely changing the way business is done in developing countries. I can't remember the exact study but there is a correlation between the number of mobile users in a developing region and the GDP growth. I believe that the availability of mobile phones at competitive rates (not government controlled) are probably doing more to help countries develop than many aid projects. Landlines in many countries have been government regulated and painfully inefficient. When I was in Kenya, my host family received a visit from the government-controlled telecom company to fix their landline. They had been waiting four months for them to show up.
In your case, with the schools, I think that is an example of a good case of charity. However, many charities and aid organizations are under pressure to show results in X number of months rather than in X number of decades. Many decisions about aid projects are not even made in the areas themselves but are made back at the head offices or at the government level in places with completely different realities.