It's worth noting that just because ST has randomness and is still a good game doesn't mean that it wouldn't be a better game without the randomness.
Isn't ST HDremix going to have the rebalanced mode, worked on by Sirlin and other top players, which removes this randomness? And, in fact, that mode is going to be used in Evo?
Sounds like, given the opportunity to remove that randomness, the best players of ST choose to do so (as well as some other tweaks). This is very much like how Smash players turn off items, since they can choose to do so.
So probably items, handled well, don't break the game sufficiently for traditional SRK players to deem them warranting a ban. However... you ban items in Smash for very different reasons than you ban most anything else in a fighting game. You might ban Akuma, for instance, since the character design of every other character makes it impossible for them to win against a good Akuma. You might ban some type of glitch for making the game not able to be played (like the IC freeze glitch in melee). You might ban a stalling tactic. These are all the types of things that need to be shown to be exploitable in a truly huge sense to warrant a ban. Items are different.
You're not banning items for any of the types of reasons that other fighters ban things. They're relatively unique in as far as this goes, you don't see these types of neutral 3rd objects in other games (as noted by UltraDavid, etc. etc. on SRK). If you have them on, sure, you have to make adjustments of which items are OK and which aren't, from an overpowered perspective (as you would with any traditional fighting tactic). The argument for turning them off is basically that they are too random, which is a bad thing in a competitive game in general. (Yes, exceptions exist, like MTG, but note that is so successful because the majority of the mechanics in the game basically boil down to ways to manipulate luck. Card draw, card filtering, search, shuffle effects, mulligan, cycle, etc. etc. Furthermore, card games which remove luck exist. See: tournament bridge play.) It's just like how, given the chance to remove the randomness in ST, Sirlin is doing so. Sure, this changes how the game is played. The randomness has all sorts of consequences, as that Sirlin post noted. That doesn't mean that the game won't be better for it. Evo is adopting the revised ST. Turning off items is the same reasoning. Given the chance to remove a huge source of randomness from the game while still being left with a thoroughly competitive, deep, interesting, viable competitive game, then of course you remove the randomness. That's why people want to remove items in Smash.