Taylor and Phillips write:

The kind life — the life lived in instinctive sympathetic identification with the vulnerabilities and attractions of others — is the life we are more inclined to live, and indeed is the one we are often living without letting ourselves know that this is what we are doing. People are leading secretly kind lives all the time but without a language in which to express this, or cultural support for it. Living according to our sympathies, we imagine, will weaken or overwhelm us; kindness is the saboteur of the successful life. We need to know how we have come to believe that the best lives we can lead seem to involve sacrificing the best things about ourselves; and how we have come to believe that there are pleasures greater than kindness…

In one sense kindness is always hazardous because it is based on a susceptibility to others, a capacity to identify with their pleasures and sufferings. Putting oneself in someone else’s shoes, as the saying goes, can be very uncomfortable. But if the pleasures of kindness — like all the greatest human pleasures — are inherently perilous, they are nonetheless some of the most satisfying we possess.

[…]

In giving up on kindness — and especially our own acts of kindness — we deprive ourselves of a pleasure that is fundamental to our sense of well-being.

The article seems to think that culturally kindness is associated with weakness. 

I haven't found that to be the case. Have you?

I find kindness akin to confidence and strength of character. How do you view kindness? 

I agree but also I note that kindness is a habit that can be practice. 

The more we practice kindness, the kinder we become. 

I think the character traits that stem from this are compassion and empathy. 

Acts of kindness create more compassion and empathy. 

Agreed.  Practice kindness until it becomes one of your founding principles.

Practice kindness until it is part of everything you do.

“Practice kindness all day to everybody and you will realize you’re already in heaven now,” Jack Kerouac wrote in a beautiful 1957 letter. 

“Kindness, kindness, kindness,” Susan Sontag resolved in her diary on New Year’s Day in 1972.

And yet, although kindness is the foundation of all spiritual traditions and was even a central credo for the father of modern economics, at some point in recent history, kindness became little more than an abstract aspiration, its concrete practical applications a hazardous and vulnerable-making behavior to be avoided — we need only look to the internet’s “outrage culture” for evidence, or to the rise of cynicism as our flawed self-defense mechanism against the perceived perils of kindness.

We’ve come to see the emotional porousness that kindness requires as a dangerous crack in the armor of the independent self, an exploitable outward vulnerability — too high a cost to pay for the warm inward balm of the benevolence for which we long in the deepest parts of ourselves.

Kindness' original meaning was kinship and sameness.

The most paradoxical part of the story is that for most of our civilizational history, we’ve seen ourselves as fundamentally kind and held kindness as a high ideal of personhood. 

Only in recent times — in large part thanks to Emerson — did the ideal of independence and self-reliance become the benchmark of spiritual success. 

The need for belonging has become an intolerable manifestation of vulnerability — we’ve stopped believing in our own kindness and the merits of mutual belonging, producing what poet and philosopher David Whyte has elegantly termed “our sense of slight woundedness.” 

On a mission to examine “when and why this confidence evaporated and the consequences of this transformation,” Taylor and Phillips write:

Kindness’s original meaning of kinship or sameness has stretched over time to encompass sentiments that today go by a wide variety of names — sympathy, generosity, altruism, benevolence, humanity, compassion, pity, empathy… The precise meanings of these words vary, but fundamentally they all denote what the Victorians called “open-heartedness,” the sympathetic expansiveness linking self to other.