UPDATE 5:40 p.m. EDT: Wisconsin Gov. Scott Walker responded to the president's taunts, saying the issue is freedom. "What we did was ultimately about giving people the freedom to choose whether or not they want to be in a labor union or not through right to work. That's pro-worker," Walker said.

Walker did not respond directly to the criticism about comparing his union-busting tactics to handling the Islamic State group or comment on the state's inability to generate the number of jobs he predicted would follow the right-to-work push.

Original post:

U.S. President Barack Obama ripped Republican presidential candidates as being against American workers in a speech at the Greater Boston Labor Council's Labor Day Breakfast Monday. Obama's Labor Day speech to a room of about 765 people criticized GOP leaders for espousing strategies he said would hurt the middle class.

The president joked he was "so glad I’m not on the ballot" in November, but went on to slam GOP leaders for their stances.

"Now we're starting to hear a lot about middle-class values," he said. "Some folks seem confused about what exactly that means." Obama then went on to list details in support of his economic positions but later returned to criticizing Republican presidential hopefuls. 

Without specifically referencing him by name, the president ripped Wisconsin Gov. Scott Walker for his comments about a plan for combating the Islamic State group earlier in the year, in which he said, "If I can take on 100,000 [union] protesters, I can do the same across the globe," CNN reported.

"So one candidate, he is bragging about how he destroyed collective bargaining rights in his state," Obama told the union crowd, which predictably responded with boos. "And says that busting unions prepares him to fight ISIL."  The crowd responded with laughter.

"I didn’t make that up. That’s what he said," Obama said before adding with an air of disbelief, "Really?"

Obama, Boston U.S. President Barack Obama speaks at the Greater Boston Labor Council Labor Day Breakfast in Boston, Sept. 7, 2015. Photo: Reuters

During his speech Obama also said many Republican leaders claim to support the middle class but their practices boost the rich. He was especially critical of the concept that cutting taxes for the wealthy and looser rules would create prosperity for the country.

"Republicans in Washington are trying to rebrand themselves as the party of the middle class," he said. "I’m glad they’re doing it -- really. ... But you can’t just talk the talk.  You got to walk the walk."

Obama also unveiled an executive order requiring companies that contract with the federal government to give their workers paid sick leave. The president also talked up the accomplishments of unions at the breakfast, referencing the 40-hour work week and the concept of  weekends off.

He also made sure to reference a very recent -- and quite prominent -- case of a union triumph by bringing up a local football star. Obama talked about New England Patriots quarterback Tom Brady and his recent court victory over the NFL -- backed the NFL's players association -- that vacated his four-game suspension for an alleged role in a supposed scheme to intentionally deflate footballs to gain a competitive advantage.

"Even Brady's happy he's got a union," Obama said to laughs and applause. "So you know if Brady needs a union, we definitely need unions."