To notice the cracks in Rossi's experiments you need to be looking for them - and people looking for them are - well - likely to be people who are naturally skeptical. Anyone not like that would detect the natural skepticism and reckon that such people must be biased, as often they are.
The problems with the 1-year test were readily apparent, as described in Exhibit 5, and by the photos of the warehouse. You do not need to be a skeptic to see them. I would say that to deny them you have to blinded by wishful thinking.
It was not so difficult to find errors in the Lugano test. McKubre and others found them, and described them. See: