I don't really know this area, but this seems unwise politically. An argument that funding him would be good for mathematics (not open source in mathematics) would seem a better tactic. As would a general, positive pitch for funding, possibly with the addendum that many people suggest the Simons foundation, but "unfortunately they turned us down and decided to fund a closed source alternative instead" may have come across better.
Perhaps but I can understand his frustration her as the work he does is tremendously valuable and a relatively small amount of money would be a massive force multiplier for it.
