Eventually, they released a "Windows 10 Edition", based on the Bedrock code base. This version is incompatible with Linux and macOS, and can't play multiplayer with the Java client.
Later, they renamed the Java client from "Minecraft" to "Minecraft: Java Edition", and renamed "Minecraft: Windows 10 Edition" to "Minecraft". They also started railroading buyers towards this game formally known as "Minecraft: Windows 10 Edition".
As a result, the definitive version of Minecraft, the version someone gets if you just tell them to "buy Minecraft", does not work on Linux or macOS. If you're a Linux or Mac user, and you want to play Minecraft with a friend who uses Windows, you're probably going to find that their game is incompatible with yours. Because as a Linux or Mac user, you don't get to play the version branded as simply "Minecraft". You're off in your own separate world, playing the incompatible game known as "Minecraft: Java Edition".
To add insult to injury, there's nothing technically preventing the game now known as "Minecraft" from working on Linux and macOS. "Minecraft Education" is a product based on the Bedrock code base which is available on Linux (well, ChromeOS) and macOS.
Does that make it clearer?