If nobody believed in superstition it would be unable to hurt anyone
If you can't doubt miracles and magic then what
can you doubt?
We take it for granted that it is okay to have doubts about anything at all. Miracles then would be more deserving of being doubted than anything. And the stranger the miracle and or the bigger the more doubt you would need.
Even if we convict a criminal, we may say the evidence we have shows he did it. But you are not saying you will close your mind against any new evidence that comes to light that may point to a different conclusion. Your acceptance of the evidence has an element of doubt in it. So you should be prepared to doubt miracles too.
There has to be some category of claim that must not be believed without sufficient evidence. If it is not miracle or the supernatural then its nothing! This is not about being biased or unfair. It is what we need to do. That's all. There are some things that must receive disbelief or scepticism no matter how dependable the testimony of the witness seems to be. There are some things that even good testimony isn't enough for. Testimony is not a reason to believe in miracles. There needs to be a limit on what is accepted on testimony. And if it is not miracles and the supernatural then there is no line.
There is no hard evidence for miracles - just people testifying that they happened.
Miracles even if they happen call for doubt not belief.