Loews Hotels said it was canceling the event, citing the mob attack on the U.S. Capitol.
Invites were sent days after Universal's parent company cut off political donations to Hawley and others who voted to block certification.
Knott's will now extend passes into 2022 for each day the park remains closed.
The event will see the return of the Mardi Gras Tribute Store, but larger concerts and parades will not be held thanks to COVID-19.
2021's new attraction lineup ranges from record-setting roller coasters to an immersive hotel experience.
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Universal Orlando's third theme park has put on hold in April due to the pandemic.
The trains will only feature lap bars, no over-the-shoulder restraints.
U.S. citizens remain generally prohibited from entering Japan and foreign tourists may remain banned until spring 2021.
The layoffs "are not new or unannounced," Universal said.