Peach without Ganondorf experience is not very scary. A peach WITH the experience is...Armada versus Kage. I'm sure we all remember that relentless ass whoopin'. You just can't really get in on her, and if she has a turnip in hand she can stuff you. When the match up is played right it's not 50/50. It's probably 55/45. It's very close. Ganondorf can use max range aerials to win the matchup if his spacing is good enough, but a good Peach is just going to make that impossible with turnips, and then it turns into a bunch of guessing games, but unfortunately Ganondorf can't really guess wrong. Peach has leeway to screw up, and she can wall harder than him. I've played a good Peach before, and some days he just is onto me. No amount of wavelanding, trickery, or spacing is going to save me from getting pushed into a corner, and getting stuffed by a float-canceled aerial, or a dash attack. We also can't edge-guard her high at all.
I doubt they are much better than you if they are losing a 50/50 matchup as you guys believe. By nature you should lose if they are much better playing an even matchup. That's like saying Gary Kasparov would lose to some expert level chess player when he doesn't handicap himself...of course he'd never lose.
Also, you don't really have the range on her. On the ground you lose, and in the air it's really about timing. If the Peach times it right she'll go right through your fair. I doubt any of you have played Peach's that are really crazy good. Peach has a lot of potential, and most don't even scrape the beginning of it. Only Armada actually fleshed out the character--and my friend who plays Peach uses a lot of those combos, and edge-guards. And when he actually is dialed in on me it feels abysmal. I jump and I die. I stay on the ground and I get grabbed or dash-attacked, or float-cancel pressured if I don't try to run away from it. If you get hit with any sort of float-canceled aerial it's always a jab->grab or dsmash or grab. You don't have the options she has, or the speed, or the combos. Not sure how you're beating people so much better.
You can't edge-guard Peach unless she commits to her umbrella and there are still things she can do to interrupt you on the way back. Most just lazily drift back instead of flickering it to interrupt you. If she goes into float I'd love to see how you edge-guard her. It's a guessing game at best. It's not as formulaic as the spacies--you actually have to get a read.
On paper it's definitely not our favor [do we even have shield pressure like she does? Nope.], and in real life it probably isn't either. And certain maps absolutely wreck us...like Dreamland, or FoD. She has better stage control, and better presence EVERYWHERE on the damn screen. I want you guys to play a Peach who really knows how to be aggressive and it's NOT an easy matchup; albeit the lackadaisical Peach is a cakewalk.
Anyone notice how Armada just runs into Kage fearlessly and then shields? Kage can't do anything about it. Armada just runs up to him and puts his shield up and punishes. What can Ganondorf do against that? Grab? It turns into a guessing game that doesn't really work...those were all frame traps that Kage was falling into because he was forced to answer Peach's pressure. You never feel pressured when you play those Peaches I'd imagine. Or at least not that pressured.
I mean if I used your logic I'd think the matchup was fine. I beat the best Peach on the Island out here in tournament, but he's still trash compared to what a Peach really could be.
Also, it's typical of a Ganondorf player to assume others are much better than them at the game because it helps alleviate the feeling of playing an awful character when one loses. You're probably a better player than all of those Peaches, and you're just holding yourself back playing Ganondorf. Just because someone is more technical doesn't mean they are better. I've played against tons of people who are more technical than me because of their character, but I beat them because of good decision making. If he at least had shield-damage he'd be amazing because then you could shield-poke or something. He just has no viable play-style that works except for max range poking, and mix ups.