can you really say you know what your child will feel in the future?

I don't really think you can make those assumptions for your child, per your post. You can make guesses as to how they might feel (and you might be right in some cases), but to presume you will know how they think or feel about anything is not a guarantee. And many psychologists would say that it's actually pretty unhealthy to assume you know any thoughts of feelings of your child on an issue as big as this one.

You can flip this around: what I imagine what my child would feel in this situation if I didn't tell is that they would be very, very angry and confused. And would wonder what other things I've been hiding from them.

Also, one blog is one data point. There are plenty of DE moms who have told and are very glad they did. From what I've read, the majority who have told do not regret it.

In the end, we all have to do what we feel is best for the child. None of us really know which way is 'wrong' or 'right' at this point. And we may never have an answer to that question as individuals are unique and have their own feelings. Or, society may evolve to a point where this is a non-issue and there is no longer any shame that people feel they need to hide from.

For myself, the fact that the primary motivator for not telling involves avoiding negative feelings such as shame, embarrassment, rejection, etc., is every reason to tell. You can't run from those things in life. Add on top of it the risks of a child not knowing their full health history just makes it all a bad idea.