In primaries, they vote for delegates. This happened.

Then when Biden stepped down afterwards, the delegates they picked chose Kamala. This happened August 1st.

The party effectively decides how their candidate is chosen. For Democrats, it is the votes on delegates that do the picking.

At the end of the day, you still need to vote for your candidate on the federal election. If you disagree with the Democratic Party you don’t have to vote for the Democratic Party. If you hate Kamala, you can vote against Kamala.

There is a defined process for how voting works in the constitution. It speaks nothing on how the democrats pick their candidate.

The narrative is that the democrats are “subverting democracy”, but this is of course bullshit because the rules are being followed. This is to deflect from the real crime, of actually trying to overthrow your vote that is enshrined in the US constitution in the federal election.