Ion did make a statement at that time. When everyone was saying that they would definitely happen because of the models, animations, customization, etc that we were seeing being added to them, Ion deliberately came out with a statement about how, and I'm paraphrasing, "just because you're seeing models with more customization doesn't mean they'll be playable races! We're actively doing that with npc races to give them more variety". Which was definitely Ion trying to cover up and distract from them being a thing to keep some element of surprise. And again, it was not the first time. When we saw the lightforged draenei in Argus before their introduction as playable it was the same story.
Ion saying covenant races are "not planned" or being ambiguous about it, should not really sway anyone one way or the other. He will actively mislead you about future surprises if there's added benefit to it. And I don't blame him at all, I'd probably do the same. If he just came out and said they'd be added, it would ruin the surprise, plus people would be mad for as long as they were not made available, and even worse if they got delayed (like kultirans and zandalari were).