Absolutely. One of those rights is equality. Certainly, using 10% is just not equal. If you wanted to use $1,000, $10,000 or $100,000 and say, “That's the limit that can be given by a third party organization that is not using some bank account where individuals deposit money,” I'm all for it, because then it would apply to everyone equally. When you have such a diversity of third parties, 10% is certainly not equal.
My view is that's a limitation on the freedom of expression that is simply not justified in a free and democratic society.