Yep, people sink literally thousands of hours in to a single game. Some popular games literally punish you for the time you spend not playing the game or give you daily rewards so that you log in frequently.

The op was specifically talking about minecraft - it has none of those dark patterns, it's just a good game.

It's literally virtual building blocks (+ hack and slash combat and crafting and exploration etc). Would you have the same level of derision for kids who sink thousands of hours into playing with lego? Kids have a lot of spare time to kill.

Finding diamonds in minecraft isn't gambling mechanics?

Dig down to just above bedrock, and dig a long, level, 2x1 strip. You'll find diamonds within a few minutes. Each block destroyed this way exposes three potential diamond blocks. Finding diamonds is far more of a knowledge problem than a gambling one. Inefficient mining can make an 8 minute hunt for a diamond vein take over an hour. Also diamonds are a pretty hardy good, once you have a sword, pick, and armor, there isn't a huge reason to seek more until you consume those goods.