True, in practice. But it's an abomination of legal logic, to take a law that does NOT penalize something, and assert that the decision upholds a law that does penalize something.
The law did penalize something. He was fined for feeding it to his chickens on the premise that had he not grown enough wheat to do that, he would have had to buy it on the open market, which affects interstate commerce.
IOW, the federal government can control the tomato plant that you planted and that you eat, because that bite out of that tomato would have otherwise been a bite out of a tomato bought on the open market, affecting interstate commerce. Even if you would have bought the tomato from a local farm, that farm produced tomatoes sold on the open market. Even if that farm didn’t sell outside the state, any farm in the state producing that tomato meant one tomato that didn’t have to be imported from out of state, thus affecting interstate commerce.
This is a legal absurdity. A person must be insane, stupid, devious or all of the above to think that the Founders though the federal government could control individual actions with such granularity.