If this was honestly the case......then this matchup would be bordering along the lines of a hard counter...like a 7-3 or a 8-2 <_<.
It is... Actually to be honest a lot of Wario's matchups are like that for him because he can do that and they can't catch him. Take a Snake for example to Brinstar, RC, CS, or any stage with some room and you can seriously win by just hoping around all day. You can even do it on flat stages that are relatively small and he can win. You can do this to Dedede, who we used to think hard countered us, until we realized we don't have to approach him and we win. Same for just about every hard counter Wario had, they are now in his favor when you force them to approach.
At the very top level, once Wario starts to play gay, he is really hard for any character to beat once he gets a lead. When most people talk about his matchups, they ask how he will approach. What they should ask instead is "How can I catch him once he gets a lead?"
Edit:
Someone's gotta get hit sometime. To put another spin on it ... Wario is just as vulnerable approaching Zelda as Zelda is approaching him. I'd like to see Wario try to approach a Zelda who adamantly will not approach without taking a lot of damage in the process. If Wario is running around trying not to get hit, it just takes one correct guess with an up air or lightning kick to give Zelda some momentum. Heck, nair actually has useable priority in this matchup.
I don't get hit when I do this. If Zelda is slower than me on the ground and in the air, then how do you expect for her to catch me? If she goes in the air, I can try to jump above her, retreat, go through her with an airdodge or fast fall an airdodge, I can do a lot of stuff.
She cannot reasonably expect to Catch Wario while he is running around. Zelda is quite easy to approach compared to Wario, he can actually catch her, work his way inside, super armor a move, etc. If he loses his lead, all he has to do is go hit you and get it back, where as Zelda is struggling to hit him period and when she does she can't run away from him all day.