Stern questioned how Spicer could "not know that Hitler marched his own people ... to concentration camps and turned on chemical gas".
The Jerusalem-based centre urged Spicer to visit its website to learn more.
Here's a quick evolution of Spicer's apologies in the last 24 hours, starting with the initial comment-one that could very well make it hard this time for Trump or his administration to ignore the demands for Spicer's pink slip. "But if I'm President Trump, I'm like, well Jesus Christ, we're a laughingstock".
Cramer was played a clip of Spicer again apologizing for saying of Assad, "you had someone who was as despicable as Hitler who didn't even sink to using chemical weapons".
The White House did not immediately respond when asked to comment on Pelosi's statement. Spicer said Trump's position should not be "a shocker" to anyone.
Speaking at a local town hall meeting with constituents on Wednesday evening, Rep. Mike Coffman, R-Colo., said Spicer "needs to go" because he is not serving President Donald Trump well.More news: Prince Harry opens up about his depression after Princess Diana's death
"If you basically put down a red line and say don't use chemical weapons, and it's been enforced in the Western community, around the world - worldwide community for decades - don't use chemical weapons", Mr. Matthews said in 2013 on MSNBC's "Morning Joe".
Cramer initially said "I think he apologized and that's the end of it".
On Fox News tonight, former White House Press Secretary and The Five co-host Dana Perino spoke with current White House Press Secretary Sean Spicer and addressed the controversy yesterday over his remarks about Hitler.
"Your comparisons between Assad and Hitler were not only historically inaccurate but they also were inappropriate and offensive", said ADL CEO Jonathan Greenblatt in a letter to Spicer Thursday.
Mr. Matthews said Mr. Spicer was likely referring to the fact that the former German chancellor did not resort to using chemical weapons on the battlefield even when defeat was imminent.
"There's no comparing atrocities, and it is a very solemn time for so many folks that's part of that, so that's obviously a very hard thing personally to deal with, because you know a lot of people that don't know you wonder why you would do that".