"Ex. calling for free agency while still endorsing taxation"
Libertarians do not endorse taxation.
"Ex. dismissing the virtue of public pledges and endowments to the higher good
(ex. free museums)"
Nobody is dismissing the virtues of public pledges and endowments, even free museums. What we dismiss is coercive violence as a means to those ends. There were free museums, even free schools, long before government got involved.
"Ex. if abolishing Social Security, would you otherwise put a dependent elderly person's life at risk?"
We're trying to abolish Social Security and leave nobody holding the bag. If SS goes on very much longer, IT WILL END (because it is financially untenable), and tens of millions of dependent people will be screwed. Don't blame libertarians for that! The fault lies with the contradictions inherent in statism.
Government vs. the people is not:
The public sector vs. the private sector.
The coercive sector vs. the voluntary sector (or more accurately: "The violent sector vs. the peaceful sector.")