I think the term "Kantian constructivism" as an oxymoron. Kant was a constructivist about mathematics, but not about ethics.

I wish that our culture could retain the symbolism and emotional power of traditional religion while combining it with reason and science and using the combination to enhance our humanity rather than impoverishing it by choosing the one side or the other.

I think Fichte did take it further than Kant by arguing that we can regard the moral law as objectively valid only by seeing it as addressed to us by another being, even though Fichte thought God could not literally be a person who could address us.

No theory about our bodies as mere objects of observation and calculation (as distinct from partners in communicative interaction, assumed to be free) can comprehend human nature.

When people think that moral problems can be solved by some simple strategy of calculation, that sets them up for ghastly overreaching. They think they can turn everything into a "science" the way mechanics was turned into a science in the seventeeth century. They want to turn everything over to technocrats and social engineers. They become shortsighted or simplistic about their ends, and they disastrously overestimate their ability to acquire the information they need to make the needed calculations.

The problem is that many who reject Marx do not read him, or read him only by bringing prejudices to their reading that prevent them from understanding him.

Hegel's theory of recognition is basically derived from Fichte, who is its real author.