Have you heard of the political compass? The left and right are not essentially authoritarian or not, either can be either. https://www.politicalcompass.org/
Cogito ergo sum is not enough at all. The presence of other people matters, if you look at primatology you can see that it's not just indoctrination. So perhaps we should add Nos itaque sumus. "Made up" doesn't make things unreal, it just makes them changeable. The tangible isn't the only realm.
I agree that this author is far too self righteous, and ironically this is essentially and ideological diatribe.
I've heard of the political compass, but I don't agree with it, at least not in this context.
Instead, I've created my own version of it, one that suits me as an "anarchist vs the concept of the state", rather than defaulting towards "which type of statism do I prefer?"
My version uses the scale of "anarchic" to "authoritarian", to suggest that level of control is more important than policies put into place.
To me, cogito ergo sum is the bootstrap code for developing a philosophy.
It's the first step, but beyond that, you must grow and grow, and find out what makes sense to you as a being. And if you accept yourself as part of a community or society, you can add that to your collection of philosophies as well.
Perhaps instead you have discovered a third dimension to it.
Oh my, that sounds much more true.
How interesting.