You recognize how deeply frustrated they are with you.
From their point of view you're simply being stubborn, as though you want to be depressed. As if it's a deliberate choice you're making, similarly to the way certain benighted parents believe their children are addicts out of willfulness or rebellion.
And you lack the energy to argue, much less enlighten, which is true by definition, because that's what depression is.
So that you stop returning their emails, you ignore their invitations and their well-intentioned outreach, and if they turn up at your doorstep, which is rude as all fuck, you don't answer the bell.