(USA) Why is a national ID card bad?

I hear a lot, especially in this sub, about how a national ID card is bad for privacy. But... The government has my driver's license, and my passport, and my SSN, and so much other info about me. From what I can tell, a national ID would serve to consolidate those, which would be convenient, and wouldn't be worse for privacy because the gov *already* has that info about you.

bad card national privacy usa