Some helpful quotes.
"After an impressive pause the waves continued, saying that what the denizens of few-dimensioned zones call change is merely a function of their consciousness, which views the external world from various cosmic angles. As the shapes produced by the cutting of a cone seem to vary with the angles of cutting—being circle, ellipse, parabola, or hyperbola according to that angle, yet without any change in the cone itself—so do the local aspects of an unchanged and endless reality seem to change with the cosmic angle of regarding. To this variety of angles of consciousness the feeble beings of the inner worlds are slaves, since with rare exceptions they cannot learn to control them. Only a few students of forbidden things have gained inklings of this control, and have thereby conquered time and change. But the entities outside the Gates command all angles, and view the myriad parts of the cosmos in terms of fragmentary, change-involving perspective, or of the changeless totality beyond perspective, in accordance with their will."
The Outer Gods do not "experience" things or obey any sort of cause and effect. They view existence as it truly is, which is a changeless totality beyond perspective. All things do and do not exist simultaneously, but this is such a thing that at many times, only the Outer Gods would be able to know, since they are aware of everything that has happened, can happen, will happen, and will not happen, since they exist beyond this unchanging existence and view it either as it truly is or in a series of changes, according to their will.
"Here the vast Lord of All in darkness muttered
Things he had dreamed but could not understand,
While near him shapeless bat-things flopped and fluttered
In idiot vortices that ray-streams fanned.
They danced insanely to the high, thin whining
Of a cracked flute clutched in a monstrous paw,
Whence flow the aimless waves whose chance combining
Gives each frail cosmos its eternal law."
This is basically how Azathoth "is". Existence does not have some overall meaning or purpose. There is simply the Lord of All at the center of all things, and from his passing thoughts comes the totality of everything. Azathoth "dreaming" things is can not understand, despite the fact that it is technically omniscient, is best equated to a dream, or thoughts that pass through your head when your mind wanders. A good amount of the time, they could be what essentially adds up to gibberish. Nothing for you to understand or contemplate, but instead just the chance combining of thoughts.
This is what existence is to Azathoth; a chance combining of its "thoughts" that are ephemeral and without any substance. It's not that his lack of understanding stems from actually being "mindless", but the fact that there is nothing for him to understand.
"The world of men and of the gods of men is merely an infinitesimal phase of an infinitesimal thing—the three-dimensional phase of that small wholeness reached by the First Gate, where 'Umr at-Tawil dictates dreams to the Ancient Ones. Though men hail it as reality and brand thoughts of its many-dimensioned original as unreality, it is in truth the very opposite. That which we call substance and reality is shadow and illusion, and that which we call shadow and illusion is substance and reality."
This can help us understand that, aside from Azathoth, the only things that can be truly considered "real" are the other Outer Gods, and even they come from him. Nyarlathotep is the only example we get of something receiving input from Azathoth, though we are simply told about it. The Outer Gods are not a chance combining of thoughts as everything else is, but instead at least somewhat purposeful on Azathoth's part. I suppose they could be equated to direct product of Azathoth's conscious mind and will, while existence is merely a collection of chance combinations from his subconscious. It makes sense as to why then the Outer Gods are beyond all perspectives, for they are the only things that are truly "real".