I admit, I don't see myself as a "vaccine safety advocate". I am not an arguer or debater. It's not the way I'm wired. I do think that general points can be made about the rareness of vaccine injury without having to seek to discredit specific stories, and I'm not sure what we really gain by trying to discredit specific stories if that person is extremely sure that it was a vaccine injury, versus if they're unsure if it was one or not. I feel strongly that vaccine injuries are pretty darn rare; they may cluster online, but if you take a population that is not self-selected for a higher degree of self-reported vaccine injury, you probably won't have any vaccine injuries in it or you may have just one.
Similar to a phenomenon I encounter at work: a patient calls having X symptom and wants to know if it could be a reaction to a drug. First thing I do is establish how long they have been on their current drug regimen and if they have started or stopped anything recently. If they have been on the same regimen for a long time, and they only recently started having this symptom, the odds are it is not due to the drug. Second thing I do, if there is a symptom that is potentially a drug reaction, and there is more than one candidate for what drug it could be, I look at the most likely one. For example, if started 2 meds recently and one was an ACE inhibitor, and they've developed a dry cough, it's probably the ACE inhibitor rather than the other one since up to 30% of patients on an ACE inhibitor will get a dry cough. But that doesn't stop some people from being ready to swear up and down that they a. developed a drug reaction to something they'd been on for years or that b. their dry cough (or whatever) was really due to their other medication... Could their interpretation be true? I mean, I can't prove conclusively that it is not true, but the available information suggests that their interpretation isn't the correct one.
Then there is also the matter of what it means to "prove" an injury. I don't know exactly what goes on in vaccine court and what the burden of proof is, but I know that "proof" is established differently and means something different to medical practitioners vs. lawyers/judges, so it irks me when the two types of proof are conflated.