"Niqabi women being fronted as a pinnacle of Islam & piety which is detrimental to non-niqab wearing Muslim women who are considered "not as Muslim""

Wearing Niqab is obligatory for muslim women,It has been prescribed in Islam and hence it is something which every muslim women should strive for.

"...Also, if wearing niqab wasn't associated with being the "perfect, pious woman" do you think as many women would choose to wear it?..."

So let me put it in this way that all muslim women who are considered to be an example/role models for other muslim women in Islam are the ones who wear Hijab; however NOT all Hijab wearing Muslim Women are examples because As I said Hijab is one aspect of Islam.

"...So Muslim women who choose not to wear niqab are not pure or following their religion properly?.."

PURE - We cant say;
Not following their religion properly: YES DEFINITELY