Healthy nationalism is simply a collective version of health self respect. As a general rule, nations and individuals with healthy self images are kinder, more generous, more reasonable, and more effective in all areas of life.
Just as people can be narcissistic, abusive and mean–like most of the Left now–so too can nations, and nationalism can be one banner around which those unhealthy sentiments collect. But ANTI-nationalism serves the same purpose, as does–OBVIOUSLY–supposed anti-fascism.
I continue to believe more and more strongly each and every day that anyone unable to see the darkness and evil being perpetrated on this nation cannot be an emotionally healthy person, not at a deep level. They have simply locked out their inner darkness and shadow and decided to live their lives pretending it does not exist.