The guy, BMX, is screwing with you.
As to the reasoning why they haven't alleged fraud in those court cases, it's because they aren't trying to prove fraud at this point because it's harder to prove than errors. The examples cited of not claiming fraud apply to specific cases regarding specific ballots being disallowed for alleged errors, but the principle applies to all of the legal challenges right now.
I think many on here are deluding themselves into thinking that significant enough widespread fraud can easily be found after the fact. Elections which provide anonymity by design and are controlled at a local level in many cases by partisan officials make it very difficult to prove widespread fraud after the votes have been cast and counted.
However, I would not expect fraud to be part of any legal pleadings at this point because it's only been a week. Right now they're simply trying to show enough examples of irregularities and issues to allow for a pause and a closer look. That's the short-term goal.
If they get the closer look and start tying things together, then MAYBE they can find evidence to support a legal claim of widespread fraud. But the reality that many of the more frequent posters on here haven't come to grips with it's analogous to completing a Hail Mary, recovering the onside kick, and completing another Hail Mary.
If you want to prevent fraud from changing the election results you really have to do it on the front end. Doing it after the fact is almost impossible. The only real hope of establishing widespread fraud sufficient to change the election in one fell swoop is the voting machine conspiracy theory not only being true, but being sloppy enough in its implementation to be provable. And people are getting way ahead of themselves in thinking either of those things are likely at all.
If Trump loses the challenges to the voting results, which is by far the most likely outcome, it won't have been losing the legal challenges which cost him. It will be, among other things like CoVID and him being a butthole costing him real votes, the failure of the Trump administration and Rs to adequately plan, prepare for, and prevent fraud during early voting and on Election Day and the day after.