This belief routinely ignores the fact that right wingers aren't the only ones who have access to firearms or are willing to use firearms. The radical left being anti-2nd Amendment doesn't inherently mean that they're against using firearms. It certainly doesn't mean that their willingness to commit violence should be underestimated when the party has a long track record of employing violence to achieve an end.
Conservatives own 2/3 of all fire arms in the US
Conservatives are in the majority in professions that are in gun ownership, police, state troopers, etc
Conservatives are and have been in the majority in the US military
The leftist army in opposition, is comprised of spoiled aged college kids with George Soros $$$ in the vast majority, that don't have a clue on guns and military operations, that are blown up to a Goliath through MSM smoke and mirrors in propaganda
The conservative army is comprised of gun owners, police, firemen, farmers, military, blue collared workers, truck drivers, you name it, that will die to protect America, her constitution, and freedoms
The untrained, unarmed, liberal left willing to fight, would be out numbered 15/1 a conservative figure
A outright civil war with the left, with real battle lines drawn, wouldn't last a week with the liberals taking 80% of casualties a conservative figure, realistically at 95%
God Forbid