"He won because the election was rigged". So saith the loser and you know what. He is right. How was it rigged?

It was "rigged" to withstand tampering cheating sabotaging undermining.

It was "rigged" by people who voted honestly.

It was "rigged" by the election authorities who whatever their partisan political views had nothing to do with their duty to make sure the election was fair and just and right.

Such "rigging" the loser and his adoring worshippers cannot apparently tolerate.