The problem with Yang (and I’m guessing many of the failed candidates who’ve joined him in this) is that he doesn’t actually understand what government does or how it works. So he thinks it’s easy and proposes overly-simplified solutions for difficult problems. Public policy is a specialized field that does actually require experience to do right.
We’ve just seen what happens when government is attempted by inexperienced outsiders: disaster. Even the things that 45 and his administration attempted that weren’t evil and self-serving failed in catastrophic ways and caused harm because they didn’t understand the process and parameters they were navigating. Even if Yang’s team managed to be less evil, they would still break things while fumbling around an unfamiliar system and discipline - and when you break things in government, you’re breaking people.