You were right about your own taste. You may have been right about the taste of many other people as well. But as a general principle, you were wrong.
Fiction is fiction. Fiction is all the stuff that didn't happen but should have. There is no part of life, experience, or history that is not ripe for fictionalizing.
This notion of stuff that didn't happen but should have is important. Stories are part of how we make sense of the world and of our lives. (I think you could make a good argument that stories are all of how we make sense of the world and of our lives.) And because they are about making sense of lives that may not actually make any sense, or that may only make sense in the next life (if there is one), they are often neater and simple than reality. But they can also be wilder and weirder than reality, because it is often in the wild and weird that we find, or at least highlight, the things that make life make sense to us.
Alternate history is a way of making sense of the world by examining consequences. What if X had happened instead of Y? If we can project the consequences of that, we understand something about the way human affairs develop.
But if stories are about what didn't happen but should have, some people will have different tastes in stories because some people will have different views about what should have happened. (This is not simply a moral question. It can be about what would be cool. It can be about what would make human life make more sense.)
To some, feeling comfortable in their skin involves pinning down as many facts and their causes a possible. Supposition contrary to fact is anathema to them. They may enjoy historical fiction because it feels comfortably close to fact. They will be proportionally uncomfortable if they suspect that anything that happens in the story is contrary to established fact. (They often have a naive and trusting view of just how established established facts really are.)
Those people are never going to like alternate history. They are never going to like four buttons on a lady's glove in an age where there should be five.
Given that they take comfort in surrounding themselves with a buffer of established facts, they are quite likely to assert that their own taste is a matter of established fact as well, that a style they don't like is simply a violation of the natural order of things.
But they are not the whole of the audience. For many of us, the things that didn't happen but should have are wildly contrary to established fact, and may call established fact into question. Some of us like nothing better than to trample an established fact underfoot, spit in its eye, and call it's mother a whore.
Fiction is fiction and may do as it pleases. Who it pleases, is, of course a different matter. We should not ask what it is right or wrong to fictionalize, but as professionals we do have to ask what will sell. And today, at least, fiction that cleaves to fact like ivy to an oak seems to be more to the popular taste.