> But still a lot of Republicans seem to believe US is not able to organize fair elections.
This is not as true as you are being led to believe. The media in general looks for extreme opinions to make news, so they'll find the rare person who believes this, and then write as if it's a majority belief.
I experienced this first hand - I watched a journalist interview tons of people, most had centrist opinions, then the finally found the person with the extreme opinion - and that was what aired that night (I specially made a point of watching).
The partisan divide is real, but what's not obvious is that it's being created by media who is desperate for attention, because that's how they get paid. They'll tell Democrats look at those horrible Republicans, and post stories of Republicans behaving badly, then the media on the other side will do it too (not as much - most media outlets are liberal leaning).
Democrats don't seem to realize they are being manipulated by stories featuring the worst that media can find, and they think that it's representative of people as a whole, so they'll start saying really nasty things - which is just more fodder for media to publish.
I wish they would make it illegal to post a minority opinion without clearly saying that it's a minority.