Yesterday Joan Rivers handcuffed herself to a Costco shopping cart and exercised her God-given right to Godwin herself on camera.

The 79-year-old was holding an unauthorized book signing while protesting Costco’s violation of “First Amendment rights” … because the retailer refused to stock her new book.  And as we all know, forcing stores to sell books is what freedom of speech is all about.

Rivers was eventually escorted out of Costco by police, but not before using a bullhorn to declare the chain’s decision “the beginning of Nazi Germany.”

Today, Rivers thanked supporters for backing her ever-so-noble free speech crusade.

Daughter Melissa Rivers tweeted in support of her mom.

Er, okay. That’s a lovely sentiment, but maybe it’s time to offer your hero a lesson or two in how that Constitution thingy works. Here’s some help from the Twitterverse to get you started.

But Nazis! And censorship! Or something.

Rivers also complained via Twitter that Costco stocks “Fifty Shades of Grey,” a series with explicit bondage scenes.

It’s soooooo unfaaaaair!

Once again, this is not government censorship. And it’s the cover of Rivers’ book, not the content, that has Costco buyers shunning the title. Via Newsbusters, here’s why Costco won’t carry “I Hate Everything … Starting With Me”:

The chain of 429 US stores is said to have banned the title because of fictional quotes on the back cover, including Marie Antoinette saying: ‘I don’t like her. Let her eat s–t’ and late basketball player Wilt Chamberlain – who claimed to have slept with 20,000 women – saying: ‘Even if I were alive I wouldn’t f–k her.”

Cameras, handcuffs and constitutionally illiterate ranting? Looks like Rivers exercised her First Amendment right to pull off a cheesy publicity stunt.