You don't think of lightning, the meteorological event, and think of the color black. You think of a lightning strike - pardon the pun but the actual raw charge of electricity in a thunderstorm - as appearing white, or purple, or blue. That being said, the Tampa Bay Lightning franchise had been utilizing black for almost 20 years before the 2011 logo and jersey system revamp. With the new uniform system, black all but disappeared from the jersey system (a black outline on numbers and on gloves and not much else). That hit some people the wrong way.
Before the uniform/logo upgrade, I wrote a post about a lack of traditions for home games at the building now known as Amalie Arena. A tradition that I took for granted, though my writing was about the arena and not the other aspects of the franchise, were elements incorporated in the jersey system: black in the team uniforms, the victory stripes under the arms, the bolt of lightning on the hockey pants, they were all little things that we were so used to but weren't exactly labeled traditions with the club.
The profound change of the primary jersey color from black to blue was upsetting, but many have gotten used to it and embraced it. Others cling to the 2007 jersey system (with the black smock-like home uniforms that hid white and blue too well) and logo as what they'd prefer, while others still find the white/black/silver/blue of the original team uniforms as the uniforms and logo of the Bolts. If this is resisting change, which is a constant in this world, or nostalgia depends on person to person. That being said, the older Lightning uniforms are still embraced by some, proudly, with partial thanks to black and the crest logo that displays "Tampa Bay" proudly.
So why black, why does it matter? The tradition, as was stated, is ours - that color had been part of the organization's history for just shy of 20 years: from inception into the NHL to the brief success of the mid 1990's, it was with us through the trying and woeful seasons around the turn of the millennium, and it was what the club wore when the ultimate success - victory and the glory of Lord Stanley's Cup - was earned. It wasn't just a uniform color, it was our color, it was part of what we associated with the club. It was part of its identity with fans much like orange is still associated by many local fans with the Tampa Bay Buccaneers of the NFL. The Bucs may have played terribly with those colors and the Bucco Bruce logo, but locals still took pride in those symbols.
We associate lightning and our Tampa Bay Lightning with black, or at least have a fondness for it, for the simple reason that black is the matte where lightning shows up clearest, brightest, and most profoundly. It's the night strikes and in the gloom of a storm where lightning is most intimidating, putting on its grandest spectacle for those who witness it. While a lightning strike itself isn't dark, it's black where a strike is most memorable.
That's why fans of this team embrace the black - because of the memories that shine the clearest from the past are set against those colors. That's why the new alternate uniform will likely be embraced by the masses, because that crest, our crest, shows up upon it in most simple and stark fashion that the fans should wear with pride.