It’s a loaded critique. It could be used by the poster to mean if he didn’t open up to his insecurities but it can equally be interpreted as “if he doesn’t open up to stuff he’s planning to do” (confident men tend to do that and deal with the insecurities themselves rather than dumping it on their partners — who often have little idea how to help them with that).

Someone that writes this tries to win the debate with it on the presumption that the critic has no answer for it. But you did well unpacking it.