I doubt it had anything to do with the backlash. Likely it's poor corporate communication within Nintendo. Legal likely sent the notice to EVO as a matter of course after their YouTube policy, and then another branch of NoA found out and were like "they said what? No, no, EVO's cool."

Or maybe people don't understand  the meaning of words "do not have permission"

If Evo had to get rights from Nintendo to stream the game but never bothered to (never got permission), that's Evo's fault.

Thank goodness they are allowing EVO to stream Melee. Don't be that guy, Nintendo.

I guess I never will quite understand the small, vocal minority that to this day has such a hard-on for Melee. Don't get me wrong, it's good that Nintendo is allowing it to be streamed. Out of all three companies, I would in all honesty give them the "most fan friendly" award. But while Melee was a great game for it's time, to me, Brawl pretty much outdid it in every conceivable fashion, as (despite certain things I don't like hearing from Sakurai) this new game will also hopefully outdo Brawl. I guess I just don't "get" the morbid obsession some have with Melee.

Yeah that seems to make a lot sense. That would've sucked for EB/Mother 2. 

The hell is wrong with Nintendo's decision making lately.They're not in any position to be cockslapping their fans.

Glad they made a 180, but it doesn't change what their initial decision was.

Nintendo really needs to FIRE THEIR WHOLE MARKETING TEAM!!! Nintendo's marketing the last 2-3 years have been horrendous!!! This was free publicity that they were denying and it would build hype and momentum for their upcoming Wii U version of the game!!! Unless their is a saboteur in their marketing team that is in league with Patcher that is intentionally sabotaging Nintendo from the inside!!!

Here is what happened most probably:

Nintendo has people that go around defending their IP's on several supports. The request of EVO got thrown in with the request from average joe's site. The standard Nintendo reply by their lower ranking worker is no refuse these requests in a polite form.

EVO goes public saying they got this response. Fans are displeased and this reaches the ears of higher ranking workers on the company. They immediatly order the mistake to be rectified since its not average joe's site but a show with lots of exposure.

Thats basically what happened here. The low ranking worker has no clue who these sites/organisations are and the higher one does and had to rectify the decision.
Is Nintendo clueless? No, otherwise they wouldnt have reverted the decision so fast.
Is the lower ranking worker someone who doesnt know or care about videogames? Probably yes.

Melee just had tigher control, more balance, and better characters IMHO than the Brawl!!! Plus it was built on a standard control scheme which to this day is what Smash players use as the standard!!!

Nintendo never refused anything or made/reverted any discision. They were informing Evo that they never got permission from them to broadcast the game.

If they didn't ask for permission......they didn't have permission

"...do not have permission..."