Sure, this isn't new here with the vote fraud. I'm pretty sure that both Ron Paul and Pat Buchanan got frauded out of the Republican primaries.
It's just that in this case they wanted it known that there was fraud. We can speculate about why, but they could have stolen the election without anyone being the wiser.
There could be another explanation, that Trump won by such a large margin that the system had to jacked up to ludicrous, obvious levels of fraud.
Look at all the past elections since they computerized, the presidential candidates were all the same, in fact they are buddies now and against Trump (Bush, Clinton, Dole, Romney, McCain). The agreement as to who was going to be the next president in all of those elections could have been agreed to beforehand by the candidates and if it didn't work out, the small difference in votes would be adjusted.