It's genuinely just this.

The rise of more grass-roots news sources (podcasts, memes, social media) also leads to tons of conspiracy theories, and mistrust that builds this idea of corruption being ubiquitous, just not out in the open. And yes, that happens, but this atmosphere magnifies it 10x.

So when someone like Trump does it out in the open, people are more likely to excuse it because "everybody is already doing it, at least this is out in the open".