In reply to T Piwowar.

The plugin, the source code itself, is both free in terms of monetary costs and free in terms of licensing. The ACF Blocks plugin that you download from WordPress.org is $free. You can download, use, modify, and share the code at no cost.

The plugin author specifically built it for users of the third-party ACF Pro plugin. That is the plugin's audience. He has no control over the pricing of that plugin.

Even if you are not using the ACF Pro plugin, you still get free access to the plugin's source code to do what you like with. You are granted the freedom to modify it and even make it work without ACF Pro.

This is also inline with the WordPress plugin directory rules. It's nothing new. I don't have any particular feelings about it one way or another except to say that the plugin author is missing out on a larger audience. Outside of that, the only people who can change the rules are the folks on the plugin review team.