Because Goldwater became a liberal in his dotage, that's why.
Goldwater died an abortion-promoting, gay-rights promoting, Sandinista-supporting, UFO conspiracy theorist.
In other words, a left-wing disgrace.
Abortion is not a liberal or conservative issue it is more of a moral/bioethics issue. There are liberals who are pro-life and conservatives who are pro-choice. I personally oppose abortion and if my state legislature decides to ban it that will be the right thing to do. However, I absolutely abhor the idea that a constitutional amendment could be passed which would ban the practice in all 50 states, never mind the wishes of the persons in the individual states.
To me, using a federal law to mandate abortion be illegal everywhere in the country is no different than using a federal law to mandate that civilian firearms ownership will now be illegal. By the way, neither of these ideas will go over well if you attempt them and are likely to spike mass resistance and non-compliance.
I am certainly no fan of Paul, but it is nice to see that there is a candidate in the race who actually stands up for state’s rights, which after all, was the platform of Goldwater in ‘64 and the platform that elected Reagan. It was all about state’s rights, and the idea that Washington should not have a say on the internal affairs of the respective states. It distresses me that there are many people in this country primarily evangelicals, who have carried their love of big government with them as the switched parties and now seek to use big national government in order to force upon the entire country their ideal of society, even though parts of the country clearly don’t want it.
I don’t buy the idea that there is such a thing as big government conservativism, unfortunately, fewer and fewer people agree with me.