I'm so glad for you that your ds never had a vax reaction.
I expect that the majority do NOT have the reactions my children and I have had.
Still, many families like mine face a higher chance of having reactions than they know. The red flags in our case were there, but the vast majority of doctors (let alone mommies on an internet forum) don't know that those flags even exist.
If I had had a chance to hear from parents of children with vax reactions, I would not have vaxed my kids on schedule. In retrospect, I would have been very grateful to have seen a post such as the one that you call "entirely unhelpful." I would have found it very helpful, indeed.