Yes, it does sound sensible to get rid of the bad eggs and move on, making sure those behaving inappropriately don't get a similar job and do it all again elsewhere.  It would be a shame if the good work of thousands of other volunteers is tainted by this scandal.  I also saw headlines today that "abuse is rife in Oxfam charity shops."  I don't know the full story but I very much doubt that it is "rife". 

I worry more about the very high salaries paid to charity bosses, and about the help itself possibly being inappropriate.  It may sound a great idea to send goats to a certain area, but they could end up with crops being eaten by escaped goats!

Providing fresh water can never be bad, but in general, lasting  improvements to an area can only be brought about by those living there.