The point is that this is a societal issue. One person paying doing some charity on their own doesn't solve the societal issue.
As analogy: "It sucks that my peers earn less than me because they are part of <X disenfranchised group>"; You: "Why don't you just take your extra income and give it to them?"
As analogy: "It sucks that my peers earn less than me because they are part of <X disenfranchised group>"; You: "Why don't you just take your extra income and give it to them?"