Both sides are not full of traitors. Both sides do not work to infringe on and roll back rights. Both sides to not work feverishly to continue building a systemically oppressive governmental structure and laws. Both sides do not overall fight against transparency and work to conceal crimes against our country. Both sides do not fight to make sure citizens have unfettered access to the voting booth.

You see, they use that first sentence and anecdotes to try to show that both sides are the same. It's an argument that works on very simple people and people who don't really pay attention. The party's aren't even remotely similar.

That has nothing to do with "sides."

Swiftboatiars, Two Santa Claus, Willie Horton, welfare queens, "supply-side economics," lyiing us into wars, birtherism, fascists are leftists, climate science denialism, "creation science," the Southern strategy, 12,000 plus lies since taking office, ....

Need I continue?

That builds off the point I was making.

They use the flaws of humans to show that both sides are the same when it is known that both side fight for completely different goals. There is no comparison outside of what should be expected with respect to human nature.

Please continue.

It allows people to think of themselves as worldly and knowing how "things really work", and so freeing them to dismiss unpleasant contradictory information. Also, in some quarters, it pays really well.

When the ball is on the 10 yard line, the big story is not "both sides need to cover ground to score".