Earlier quoted context omitted.
This is one of those cases, like "Zero Trust Networking" where you can't derive the meaning of a term axiomatically from the individual words. There is "responsible" and "irresponsible" disclosure, too, but "responsible disclosure" is also a specific, Orwellian basket of vendor-friendly policies that have little to do with ethics or responsibility.
"Responsible" and "irresponsible" are slippier words in the disclosure context. In the civil legal context, "responsibility" implies blameworthiness and liability arising out of a duty of care and a breach of the duty. But in the vulnerability disclosure context, since there's no duty prescribed by law, it has come to mean "social" vs. "antisocial" - getting along vs. being at odds.
Logomachy aside: "ethical hacking" was a term invented by huge companies in the 1990s to co-opt security research, which was at the time largely driven by small independent firms. You didn't want to engage just anybody, the logic went, because lots of those people were secretly criminals. No, you wanted an "ethical hacker" (later: a certified ethical hacker), who you could trust not to commit crimes while working for you.