It's all about having convincing evidence. Mere testimony isn't.
In the election cases they hinge on preponderance of the evidence. Signed and sworn affidavits are indeed evidence and places the individual into jeopardy if proven to be untrue.
The legal process allows the defendant to have the individual who completed and signed the affidavit to appear in court and be examined and cross examined. It can also allow discovery, interrogatories and depositions.
You haven't read any of the affidavits. Many contain names, times and places and attached evidence to back up the claim. But since the courts have decided to use procedural issues such as standing and laches, the affidavits never make it to the evidentiary phase or discovery.
For a group that has tried in vain to convince the American people this was somehow a free and fair election, but then resort to tactics to hide the evidence and outright refusal to allow witnesses to see the process and even refuse request to examine evidence, in itself leads to people questioning their motives.
People with nothing to hide are transparent and forthcoming. The guilty will obstruct, deny and obfuscate.