Like what? Did she get votes for him thrown out?
People have been saying for years that she had an advantage and so it wasn’t fair, but those advantages seem to ignore that more people voted for her.
He was an independent running as a Democrat, and then claiming it’s unfair when the Democratic party was more aligned with the person who had always been a Democrat.
It gets complicated because the parties can hold their primary elections however they want, independently by state because various rules mean you need a Democratic party for each state, plus the national party. So each state does it differently to some degree. Some vote for the candidate, and the delegates are assigned to vote for the winner, some get a proportion of the delegates, and in some the voters vote for the delegate based on who they support.
They use that process to assign delegates who go and vote on who the national party will select for the national election. If the first election there doesn’t yield a majority winner, they keep voting but now the delegates can switch if they want, and members of party leadership can also vote. That hasn’t happened in quite a while though, since it’s much easier to know the counts accurately before the convention and do your politics by getting people to drop out and endorse you.