There’s a difference between saying something can’t be done and recognizing that you can’t do it. For instance, I can’t run a marathon—at least not without some profound lifestyle changes. But that doesn’t mean marathons can’t be run. Happens all the time, just not by me.
Likewise, when you hear people say it’s impossible to make fun of Joe Biden, what they’re really saying is that they can’t (or won’t) do it, or that they don’t want anyone else to try.
Until recently, people mocked “ol’ Joe” routinely, including yours truly. In the Senate, an institution famous for its long-winded blowhards, Sen. Biden stood out from the crowd. His mouth was like a car with iffy brakes and a detached steering wheel. He’d start asking a question, and 15 minutes later he’d be in a treetop wondering how he got there. He abused the word “literally” so much, if there was a lexicological equivalent of child services, it would revoke custody.
The satirical website The Onion paid the rent mocking Biden. I liked its 2010 story “Biden Receives Lifetime Ban from Dave and Busters,” but its 2009 exposé “Shirtless Biden Washes Trans Am In White House Driveway” went so viral that some folks at Fark.com tried to raise money to actually buy him a Trans Am. (Ethics rules precluded it.)