TMZ/Getty
Exclusive

Cardi B I Didn't See 'WAP' Until After My Rant ... Congressman Confesses

The Congressman who ripped Cardi B on the House floor says he didn't watch her Grammys "WAP" performance until AFTER his lecture ... and he couldn't stomach the whole thing.

U.S. Rep Glenn Grothman tells TMZ ... he finally watched Cardi's Grammy performance for the first time Thursday, about 5 hours after decrying it as "inconsistent with basic decency" while lambasting the FCC for broadcasting it.

Grothman tells us he stopped watching "WAP" after about 2 minutes ... he says he was turned off by how "offensive and boring" it was.

As you know ... Grothman complained about Cardi's Grammys appearance on the House floor, saying it's contributing to America's moral decline.

Cardi quickly shot back ... calling Grothman names and wondering why the Wisconsin Republican's wasting time on the House floor ranting about "WAP" instead of tackling critical issues like police brutality.

Grothman says he was just doing what his constituents asked of him -- he tells us folks in his district complained to him about Cardi's performance shortly after the Grammys, demanding he straighten things out with the FCC when he's in D.C.

Rep. Grothman says Thursday was his first chance to speak up, and he believes young people are in his corner on this one. He says several "respectable young staffers" did not give him positive Cardi reviews before he shared his piece. Of course, they work for him ... so, those are hardly unbiased opinions.

The way Grothman sees it ... Cardi struck it rich by appealing to the lowest common denominator, and he thinks that hurts the country's moral climate.

Despite Cardi protesting, he says he's working on assembling a group of 15 to 20 Congress members to cosign a letter to the FCC about not allowing this kind of content on TV.

Click here for info about our online advertising practices.