I can't tell if the cartoonist is being sarcastic or genuine. I'm so confused 
That's the point. These cartoons would easily pass editorial muster in any smalltown shitheel paper in America. But when you run 'em in The Onion, suddenly it's satire, because the opinions they express are just dogmatic and jingoistic enough to be trenchant self-satire to The Onion's more educated audience. Context is everything!
I actually thought it was some real cartoon

Now knowing its from The Onion, its kinda scary that this comic panel/strip could easily pass for a serious thought on the subjects.
The Mark Foley one is the best. "WE ARE ALL MARK FOLEY"
I don't get that one. Is that like "we are all sinners"?
It seems like in that case, the comic is trying to clump all Senators together by saying theirs no such thing as a Innocent Senator. Thus trying to take heat away from what Foley did.
EDIT: TVC is smarter then me :'(