C'mon man, it's not about you and your struggle to find a safe place to crack your precious racist jokes. And I feel your pain. Remember those "How many pollacks does it take..?" jokes? I used to love those. How we laughed and laughed.
But seriously, the article isn't saying "so be an insensitive boor."
It's just warning of the pitfall of being "neurotic" (I mean that in the commonsense, rather than clinical, sense) in the pursuit of happiness.
Really it's only basic bio/psycho-physics: When you worry or stress out what are your muscles doing? They are tense, burning ATP molecules at a furious rate, working to get rid of waste products, and generally feeling uncomfortable.
Now relax. Take a few calming breaths, meditate, have a scotch, whatever. Just let the tissues of your body relax, despite your problems. Make sure you do this in a place where you can reasonably expect not to be interrupted, so your body can commit to it. Lo and behold, you feel better.
There's no magic, and the only mystery is why it seems so mysterious! :-)
Sure the mortgage is still due and you've got no job, but you can cope with all of this much better when your system is relaxed and tuned. Really that's the difference between animals and humans: we can stop, think, and act differently. You "should" be panicking, except that reaction is no longer adaptive.
Really all this article boils down to is: when you start to tense up, stop and take a breath instead. (Unless there really is a bear or something, then just run like hell.)
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As for the challenges of telling racist jokes, the trick is to establish the safe place first. In my cubicle at work we all trust each other enough that we can drop all sorts of stinkers and we can laugh, or throw wads of paper, as apropos. But that's because we all know and trust one another, and it's never mean-spirited. We respect each other so it's safe. And fun.
The issue when you try to have this sort of ease in a larger context is that there are "smiling monsters", racists who have the hate, the illness, in them, and those kind will use the safety to psychologically "knife" the vulnerable members of the group. When there is scope for this sort of thing to happen, people close themselves off to protect themselves, and become more sensitive to "violations" of the safety protocol (aka P.C.). Given the current and historical circumstances, I don't find it an undue burden to hew to the greater common denominator of kind and friendly speech when I'm in public, or even in most private spaces. Only among friends is it humane and proper to cut loose. Basic manners really.