Look I don't like your evaulation of Wendis or Wynn but I doubt anything I can say will change that so I'll leave it be. The game has 32 harem mates so if you don't like a few it's no biggie.
However I do feel I have to argue the point of Wynn's apology.
As strange as it is to say, the 'issue' was not fully what Wynn did to Wendis's remains. The issue was always Simon and Wynn not accepting each other's grief over Wendis's death.
When we first meet Wynn Simon flat out says they were good friends but broke apart as they clashed in taking the death of Wendis in bad awful ways. And there they were almost 30 years later, broken apart by the same thing.
Wynn did a fucked up thing, but as explained by the 3 sited above, even worse was how she did not even apolgize to what she did to Simon.
And THAT is what the apology is for, because Wynn doesn't regret trying to bring her back and she'd try it again. But she's sorry for how she hurt Simon,
because even without Wendis, Wynn still cares about Simon. And Simon doesn't just go '...' as you keep saying. His anger for Wynn doesn't just set to 0 at that point, he's still mad. However I think on some level he comes to accept that he doesn't own a monopoly on the grief over Wendis, and he can at least accept that Wynn wasn't acting in a cruel or thoughtless way, she was grieving just as much as he was.