That documentation is about Einstein Analytics, which has different semantics from other areas of Salesforce.

In Apex, the == operator is case-insensitive:

String comparison using == is case-insensitive.

That documentation is about Einstein Analytics, which has different semantics from other areas of Salesforce.

In Apex, the == operator is case-insensitive:

String comparison using == is case-insensitive.

Case-sensitive String comparison in Apex is done using String.equals(). Note also there's a few places where Apex does do case-sensitive String matching; List.contains() and Set.contains() are among them.