Because of their history. Because they are the only reason you get to play your game at an event like an EVO, or an MLG. I don't look up to anyone from any community because I've been playing since 91. Granted, I was a kid, but I've been playing as long as Valle (not saying we are the same age or have the same skill). In any event, I admire the fact that there is still a Valle in the SF scene, along with a CJ truth. I admire that Capcom has left much of what Valle has spent 20 years worth of his life learning pretty much intact, embracing the legacy of their game. When they introduced the USF4 trailer, they could show the Alpha 2 opening, Third Strike, and so many moments that span decades.
CDjr made a comment about Viscant and the "OG" fg player, to which Valle made a comment saying people shouldn't talk about OG players if they don't know the history, and that he doesn't reference "OG" MK players because he doesn't know the history, which I found sad. It's sad because most people don't know the OG MK players, no one cares, and MK9 doesn't allow any of them to shine at what they spent years mastering.
For Valle, and for many MK9 fans MK history starts in 2011. Paulo has talked about his own UMK3 stories, which I find cool, but also mind boggling that these guys, these OG MK guys who make modern MK, either don't care to or can't make a Mortal Kombat game that does justice to the actual 2d legacy of the game and All of its players, and not just pay homage to the story. That's why people look up to the SF community, at least that's why I admire them: legacy.
People can complain about all the things SF4 does wrong, but any Ryu player who has ever played the character can pick Ryu and do 98% of what they were used to doing with him in World Warrior, Hyper fighting, Super Turbo, Alpha, and Third Strike. The same isn't true for MK, because the MK9/IGAU engine is fundamentally different from 2d MK. So, while Nightwolf still has many recognizable moves, the way in which everything else behaves in the MK9 engine makes even recognizable moves seem foreign to an old player, and to many 2d fg players.
Basically, imagine Ryu's crouching jab startup going from 3 or 4 frames to 6 or 8 frames, and instead of being 9 frames total(in 3s), and 10 frames total (in SF4), it became 21 frames total....Ryu wouldn't play like Ryu, and SF wouldn't really play like SF. I like seeing Valle vs Daigo. Sadly, MK has no similar pairing.