Here's the deal ... Joe and co. were hosting a Pride event outside the WH Saturday, where he spoke passionately about protecting individuals who identify as LGBTQ+ ... especially transgender children, whom he said were seen, heard and most definitely belonged.

His remarks were embraced by the LGBTQ+ community and their allies -- but, of course, they also came under fire by right-wingers who felt he was playing a dangerous game.

Eventually, they found something on the grounds to pin their outrage to ... a flag display hanging from the White House itself, with the Pride rainbow flag slotted in between two U.S. flags.

You see, some were citing a certain part of the U.S. Flag Code -- which, yes, is indeed real -- and asserted JB was in violation of section 7, article (e) ... which discusses how U.S. flags should be displayed in public. There are 15 articles dissecting this whole topic, BTW.

Article (e) reads, "The flag of the United States of America should be at the center and at the highest point of the group when a number of flags of States or localities or pennants of societies are grouped and displayed from staffs." Basically, the red, white and blue oughta take precedent and be most prominent among an assortment of flags -- that's the "rule."

In response to how the WH arranged the flags here, one conservative -- echoing many others -- writes, "To advance revolutionary transgender agenda targeting children, Biden violates basic tenet of US Flag Code and disrespects every American service member buried under its colors." Some are even calling on Biden to apologize and/or be held to account.

The reality ... nobody is going to do squat about this -- because, frankly, it's not a big deal. More importantly, though, the U.S. Flag Code (while technically a federal law) is not enforced at all ... and operates more as a recommendation on proper decorum/custom than anything.