You're right, but framed generally like this, it's easy to skip this advice.

OP/reader, more specifically, examine that post. It is an avalanche of negative self-talk. It's a person telling themeselves and the world that they cannot do something. You can take a perfectly healthy person, turn on this cycle, and watch it destroy their lives.

Depression has many causes, but its roots that make it stick are cycles like these. Antidepressants are a parachute, but you have to rebuild the engine and an important part of that is to learn to reframe events and identify and challenge your negative assumptions.