I find it hard to believe that HN is truly pro-union when the top comment here seems to miss the point entirely, suggesting that “decent salaries” make unions unnecessary.

The reality is that workers are individuals who have to fend for themselves. Employers are naturally organized and have the power to modulate work conditions and say "find work elsewhere if you're not happy." Unions are the countervailing force to that. Even in the fairest of societies this would be true.