I guess I would call myself "New Sincere" (I prefer the term "idealist") but it does actually have a metaphysical basis.
Existentialism doesn't have to mean nihilistic. Rather, the meaning we create is true meaning. Is the only meaning that can exist. A house is a "construct" but it still exists. Just because "love is a social construct" or "truth is a social construct" doesn't mean it's not real.
Just because "Language is a social construct" doesn't mean "language therefore is empty and there is nothing behind it". No, language is both descriptive AND creative, it describes emotions and states of being while also contributing to the development of these states of being. That doesn't make it not real.
I am an optimistic existentialist, an empowered idealist. Instead of the depressed nihilist going "there was no meaning given to me so I have nothing" I go "I have the power to create whatever meaning I want and make it real".
Great article btw.