When looking at costs, one should keep a reference point in mind. For example, the ESA's total budget is ~7.7 billion euros, which is taxpayer money. However, the US alone spent about 1 billion dollars bombing the Houthis in three months (
https://www.nbcnews.com/politics/national-security/trump-ope...), and the direct military costs in Gaza alone are over 22 billion dollars (
https://www.forbes.com/sites/williamhartung/2024/10/15/the-h...). The total cost of reconstruction is estimated to be over 100 billion. The direct costs of the EU's sanctions on Russia alone cost taxpayers more than 200 billion, but these are poor estimates. We could continue in this way and examine Africa, Asia, and other regions to gain perspective.
However, it would be improper to claim that the ESA's budget for this project is a matter of diverting taxpayers' money to something negative.