Mandated, unconditional individual rights ARE collective rights and also human rights

Not when those rights are in conflict with another individual's. The classic example is the individual right to private property, but there are many others. American liberals do recognize these limits and contradictions, but accept as granted the right to private property. It's the center tenet of leftist critique, so it makes a lot of sense why there's a lot of cynicism about liberals claiming to occupy the same space. Sure, they have some overlap, but the main contention is left unaddressed by American liberals and so leave themselves open to derision.

if Capitalism is not a regulated Market System then the USA is also not a capitalism

It's a type of regulated market system, but it's defined by its mode of production being capitalist in nature. Socialist and communist systems still employ regulated markets, but collectivize ownership over productive capital instead. Abolishing capitalism isn't a way of saying we should abolish markets, but to remove capital as the mode of production