People who are interested in information hazards should study Calvinism because it's an excellent real-life example of one in my opinion. Total depravity is only one of its many views which can have awful psychological consequences.

I mean “for all have sinned and fall short of the glory of God” though. Obviously the entire message of the New Testament is that all are also offered salvation through Jesus, but it’s pretty clear that everyone needs saving in the first place.

AFAIK original sin does teach that all men are fallen and require salvation. This doesn’t mean that human nature is all bad and it’s indeed not the same as total depravity. However it’s also not true that men are born holy.

I didn't say "born holy" but if you kindly turn to Genesis you can see how the first man and woman were CREATED in Original Holiness (and Solitude, Justice, Unity).

Original sin is a deprivation of these positive qualities. Mary, for example, preserved in holiness, not simply cleansed of it. Holiness is our natural state, and so baptism returns us to that preternatural holiness that Adam enjoyed when he walked with God in the Garden.

Indeed 'created in His image' would seem to be at odds with 'intrinsically bad'.

The total in TULIP's "total depravity" is not a measure of sinfulness. It is not meant to imply that we are naturally as evil as possible in every context. The "total" is speaking in terms of the extent of depravity. That is to say, sin touches and influences every aspect of our existence. So that even in good works with the best of intentions humanly possible, there still exists an element of self exalting corruption.