That's a false dichotomy. Coordinated disclosure can sometimes optimize outcomes for some subset of users. Sometimes it doesn't. Ethical judgements in vulnerability disclosure are complicated. Sometimes a vendor and the majority of its user community would prefer disclosure be suppressed, because it saves them work (see: "Patch Tuesday"). Sometimes that impulse lines up with what's best for the world, and sometimes it doesn't. See what's so Orwellian about "responsible disclosure" now? The whole point of rejecting the term is that there isn't a one-sized-fits-all answer, to which you must comply in order to be "responsible".

Anyways: hard no to the suggestion that, in order to be a "real researcher", you have to coordinate your disclosures. To be a serious researcher, you just have to be serious about finding vulnerabilities.

(Semantic reminder: our field uses the term "researcher" in a way closer to the journalism definition of the word than the academia definition.)