You will not be alone.
Most everyone that I know has one or more family members like the ones you’ve described. Confronting them only pleases them - they want to disrupt.
Smile, knowing that there will be many in the same boat as you are today, and that we all are well aware that those who so freely spout their ignorant liberal talking points, are morons.
As they sit and stuff their faces with the bounty of this great land, your silence will showcase their idiocy and give it top billing.
You can keep changing the subject to happy family things - often that will telegraph your opinion of their opinions to the gathering and the others will quickly take up your topic in relief and solidarity.
Thanks for the support. I need it. Tick, tick, tick.