7:29 AM PT -- Haliey Welch just took to her X page to reveal she was actually at the Mets game in order to raise awareness -- and money -- for America's VetDogs, an org. that aims to pair pooches with war veterans.

Bad news for Newsday readers hoping to learn more about "Hawk Tuah" girl's first pitch at the Mets game Thursday ... one of their writers claims the org.'s bosses have barred mentions of her.

Tim Healey -- who's been writing about The Amazins for years -- said that after Haliey Welch toed the rubber and kicked off the festivities at Citi Field ... he was told he couldn't spit out anything further regarding her appearance.

Healey didn't specify why -- but it's easy to infer his honchos believe an explanation of Welch's claim to fame is just a little too X-rated for their readers.

Seems MLB ran into some similar issues ... as when it posted about Welch's afternoon in New York on Thursday, it made no references to hawks or tuahs -- merely calling her a "viral internet star."

Doesn't look like the Mets, though, cared much ... Welch told us just hours before taking the bump at the ballpark that NY officials personally invited her to be their guest of honor.

As for Welch's pitch, it wasn't the world's greatest -- but hey, it got the job done.