No one complains about science when it doesn’t affect them. There’s no movement arguing against the theory of gravity.
If your religion tells you God created us in a specific way, then evolution has to be challenged. If your politics tells you that climate change will require us to change our way of life, then climatologists must be denied. And if you want to find someone to blame for autism, then vaccines are a good scapegoat.
Sure, science can be wrong. Science acknowledges that, and there are plenty of scientists out there who would love to make a name for themselves by proving that the past theories were wrong and should be replaced with their new ones. But there’s a process for that, and it includes peer-reviewed analysis and experimentation to confirm.
Somehow, we all love to believe that we’re smarter than the people who have the education and do this for a living. It makes us feel special. And where certainly we should always challenge authority, you should have proof just as strong on your side. Saying “Well you can’t prove what causes autism so therefore my idea that vaccines do it” is not intellectually honest — you might as well say “so therefore tiny elves cause it.”
People who come up with their explanations in the absence of facts are not scientists; they are the opposite of scientists.
And there’s nothing wrong with saying “I don’t know” to something, so long as it’s followed with, “but I hope to one day find out.”