Yes of course the entire election cycle is rigged, in multiple ways.
The "primary" way in which the election cycle is rigged, is NEVER DISCUSSED:
Why are state and federal governments involved AT ALL, IN ANY WAY, in the selection process of (duopoly) political party candidates for office?
No, seriously. How is any political party running state-sanctioned primary campaigns, using state-funded voting infrastructure, state-written and -funded voters' guides, etc.?
There are no political parties in the US Constitution. There should be zero, zero, zero government support, involvement, funding of party political apparatus selection process for party-affiliated candidates for office.
Simply, there should be a set of ballot qualifications: Citizen, resident, age, and some non-monetary (not measuring "campaign contributions") process or threshold for demonstrating a minimum level of popular support or recognition: certain number of petition signatures, etc.
Parties can select their candidates any way they want (party convention, party members vote, party leaders select, etc.), and then do the necessary work to get their candidates qualified for the ballot.
That's just one of numerous fundamental electoral reforms that are needed to instill any semblance of actual democracy into US elections.