SpaceX is a private company and not accountable in the same way a government agency is.If you read the post I quoted, it was saying that SpaceX wasn't spending taxpayer dollars, which it absolutely does.
Tax payers pay the government, the government allocates some of that money to NASA. NASA spends some of the money on SpaceX for astronaut flights, satellite delivery etc.
So yes, SpaceX does receive tax payer money indirectly, but a lot of companies do, as the government still needs food, water, electricity, materials etc just like everyone else. The local wall-mart probably gets tax payer money indirectly.