Your hot take is disingenuous. He's not calling it a secret, he's calling it a personal detail he wouldn't normally share. It's not something he just volunteered out of thin air and then asked people not to tell. He's not saying "I expected you to keep my secret". He's saying they need to take some responsibility in how that information became public information.
His argument is that he's a pretty open book, and he'll be transparent if someone asks him a direct question. In essence, has no secrets and isn't going to deny a direct question. A person can be open while still not actively encouraging every aspect of their life to be public information. There's a very big difference in saying "I'm not going to hide my truths, even though I'd prefer not to talk about them".
He's arguing that if the media didn't want him admitting to drug use, they shouldn't have asked. He doesn't have to feel shame for answering a question honestly, he thinks it's more shameful to be dishonest. The shame falls on the entity who sought to make his drug use public record by asking the question. All he did was tell the truth.