In any case, this is a giant amount of money by philanthropic standards. I doubt more than 4-5 people have ever given as much for all of the things they support.
Feel free to complain about "tax loss" as in the government getting less money than they would otherwise, but it's definitely not a "tax dodge" - tax dodging only makes sense if you actually end up with more money than you would otherwise - i.e. you "earn" $100m but then you "dodge tax" to pay only $10m tax instead of $20m, and end up with $90m after-tax income rather than $80m. Multiple ways of doing that - the obvious one is moving your tax residence to a 0% tax haven, the less obvious one is to artificially inflate the value of an asset (e.g. a work of art) and then "donate it" and write off that from tax (e.g. buy it for $10k, donate it when it's "worth" $10m, write that off as a "loss" and pay only $10m tax instead of $20m).