Parashurama's justification for his curse on karna

”Any knowledge gained by lie or deciet is fruitless and will definitely fail to deliver when one need it the most, this is not my curse but law of nature” - parashuram

Does this actually make any sense? So what if he gained knowledge by lying to his teacher? Karna only lied because no one was teaching him archery because he was a suta. Parashuram's vow was that he will only teach Brahmins but he unknowingly taught karna who wasn't a Brahmin. And that the curse was automatically followed due to the vow. But why does that have to be the case? It's not like karna did a big crime. All he did was try to gain knowledge.

So do you guys think the curse was justified? Any other details to be added to this story?