I think releasing a plugin on github first is pretty typical for almost every WordPress plugin or theme that comes out. It takes a while to get approval through those queues, so releasing on github is a great way for companies or developers to gather feedback and continue testing without waiting for WordPress.org approval.

This feels like an unfair bias toward Shopify because it could be considered a competing platform to WordPress/WooCommerce.

If the same criticism were given to every product, theme, or plugin that's released in the same way, I probably wouldn't say anything, but this article feels like it's fueled by some Haterade.