Everyone does have a right to a fair trial if they've been accused of a crime by a prosecuting body. There is no such accusation that has been brought forth by a prosecutor anywhere (to my knowledge).
They did "look at the case" so to speak. As we know, they found the allegations lacking evidence to warrant their consideration of potentially overruling lower court judgements (all of which went against Trump's legal teams).
The SCOTUS has significantly more cases brought to them through appeal than they ever actually consider. Its been that way since the dawn of the court; there's no special treatment (or mistreatment if you prefer) for Trump.
Of course none of this proves there wasn't fraud significant enough to have impacted the election results. Conversely, none of this indicates a grand conspiracy either. Its just our legal system's due process; nothing more.