I have to agree with your feelings on it, OP. This reads as someone who is trying to justify cheating on their spouse by conflating a closed relationship as being somehow similar to capitalist oppression, and essentially laments they can't have their secret relationship in the open without losing the security and other benefits they experience from their existing relationship. Which if I'm being honest is pretty unhinged.
If they want an open relationship, they should openly ask their partner about it before engaging with it. If that is unacceptable to the partner, and the asker still finds their relationship unsatisfying, morally they should end the relationship instead of cheating under the justification of "is it so bad to pursue passion?".
It is the writing of a narcissict.