>...that made it difficult or impossible for them to detect fraud...
That's their claim (which is already suspicious considering their obvious motivations), but it's not the objective truth. And even if it were, it's certainly not actually evidence of fraud.
I'm genuinely surprised to hear someone claim this. The election centers handed out papers to observers telling them what the restrictions were. There were livestreams from various facilities during the process where workers were clearly seen handling election materials far away from where the observers were. There are pictures where observers are sitting impotently behind a line, watching 5+ election workers each from far enough away that they would never be able to read what's written on the materials that the workers are handling. The claims that restrictions were placed on observers which did not exist in past cycles and which would make it more difficult or impossible for observers to detect fraud were never denied in court. Instead, the defendants claimed that those restrictions did not prevent observers from being anywhere or seeing anything that they had a legal right to be or see.
>it's certainly not actually evidence of fraud
In combination with the undisputed hatred of democrats for Trump, it provides good reason for a person to believe that there was election fraud in those areas. Therefore it is evidence of fraud. It is not conclusive evidence, of course, but it is evidence.
That's their claim (which is already suspicious considering their obvious motivations), but it's not the objective truth. And even if it were, it's certainly not actually evidence of fraud.