I'm more upset about the poor writing. I never said Nero had justification to kill anyone, but that he might have a legitimate reason to be mad at Spock for not disclosing this condition. Although to be fair it's possible he did disclose it to the Romulans offscreen. I myself disclose my hearing problems when I'm called for jury duty. It's the law. There are situations where things have to be disclosed and that's why the retcon is straining suspension of disbelief.