Why what? Why would I have to stop using DuckDuckGo? Because I don't use Apple products. Why don't I use Apple products? Many reasons.

I sort of agree with the other reply (that's dead now), if not with the way they said it. Your response provides next to no information. Maybe you could list some of the reasons why you don't use Apple products? "Many reasons" provides no insight, which is especially annoying because the parent comment to yours was explicitly asking for you to explain your reasoning.

All the obvious ones: closed platforms, walled gardens, lack of repair or upgradeability, overpriced hardware, general user and developer hostility, excessive secrecy, arrogance, security bugs, planned obsolescence. Then there's the more subjective stuff: I find their UIs appalling and I'm not a fan of their design aesthetic.

But how many of these would apply to DuckDuckGo under Apple? Are you saying that they'd wall it off to "Apple ecosystem users" only? There's no upgradeability or hardware or secrecy here.