is ingratitude the worst moral crime? my interpertation of hume's Is/Ought dilema

 “Of all crimes that human creatures are capable of committing, the most horrid and unnatural is ingratitude, especially when it is committed against parents, and appears in the more flagrant instances of wounds and death.” (Hume, pg.3, paragraph 10) Why Ingratitude? Out of all the despicable things Humans do, Ingratitude may be something all Huamans are at some point, guilty of. I believe what Hume is implying is that out of all the crimes we are capable of committing, A rational person who is aware of their circumstances would find satisfaction in the circumstances they cannot control. Find gratitude, but maybe ingratitude is so bad because out of all the awful situations you could be forced to endure, you still have what you have. You’d then have to wonder, what exactly about ingratitude upsets others? I think it’s the oblivious nature of ingratitude. When people refuse to accept their circumstances can be frustrating. I agree with Hume in many ways. Hume’s Is/Ought problem is very justifiable but also Important. In a world full of unfortunate prejudices and biases that create harmful stereotypes, The Ought/Is Gap is more than crucial to remember. Hume insists that any form of induction (making pre-mature conclusions) is illogical and unjustifiable, but depending on certain circumstances, I think it is logical and justifiable. For example, using hairspray around a lit candle will likely cause a fire. Therefore; avoiding the combination is logical. It may be premature to avoid candles and hairspray altogether but making the premature assumption could save you from a fire. I understand Hume is defining moral arguments, not necessarily technical arguments, but you could replace the example with a complex moral dilemma. It’s also important to separate facts from Moral decisions and beliefs. Facts are independent in what proves them to be true, something Opinions and Morality don’t have which is logistical evidence. Some even argue that statement, like Utilitarianists and Hedonists, who fall under the Natural Law of Morality, but I think Hume sustains the most possible “Moral” results, that hold space for people to look for the gap, that is Hume’s philosophical legacy.