You cannot make the poor richer by making the rich poorer. It’s been tried and it simply does not work.
"So you'd rather spend the money on building a big wall than "send them back"
No. I’d spend the money on building a wall (and digging a ditch) AND send them back. The two are not mutually exclusive. It is known where the last non-EU port of call was for a majority of the nomads and some of £2bn can be spent sending them back there.
Any money given to “Africa” will be salted away by corrupt African leaders. Any migrants who are returned there (with my guess at the total, to the nearest whole number, being nil) will simply return. They don’t want to live in Africa, however many Mercedes cars their leaders may have. It will be, as usual, taxpayers’ money down the drain.
Can they be as inept as they appear? They can be far more so. Frau Merkel is often billed as one of the shrewdest operators in the EU. Then she says that Germany welcomes 800,000 newcomers. Strangely enough, blessed with that news, they all turn up at once. Perhaps the residents of this German village:
http://www.independent.co.uk/news/world/europe/sumte-german-village-with-100-residents-and-zero-infrastructure-told-to-take-in-750-refugees-a6717591.html
should be asked how “ept” their leader is.