Because it's, and I'll put this crudely, properly executed doublespeak and I think conservatives/libertarians need more politicians capable of doing this (not that all politicians need to engage in this, there's a place for those who primarily fight for the popularization of ideas and are uncompromising in their rhetoric, for example).
He comes across as empathetic and reasonable - and, as the article notes, without changing his view on policy. That's good politics. It becomes counterproductive when it makes one permeable to accusations of phoniness or flip-flopping - think Romney. That isn't the case here.
I'm a big fan of making the message more palatable and far-reaching without diluting the guiding policy principles and I think Rand Paul is becoming quite good at it.
ETA two additional points:
- with regards to this particular situation and his outreach to the black community, it's also smart because it makes so much harder for accusations of racism to stick
- all of the stuff he's been saying on abortion, immigration, voting ID laws, are mostly rhetoric artefacts but as they impact how people perceive him personally, bring in more to the middle of the GOP presidential nomination field, which is where the nomination is won. The only people he can lose over this are those who care a lot about fighting rhetoric and grandstanding, the HotAir peanuts gallery - as others said, having their support is the kiss of death because if one is enough of a blowhard to have their support, one isn't winning the presidential nomination. Four years ago, their support wavered between Cain, Perry and Bachmann.