I can't read the Guardian article without accepting their cookies, but I know the background to this.
The Stonewall Inn is a 'national monument' and as such it came under the Trump admin, decree that the term LGBT was to be replaced with LGB, and the trans flags were removed from The Stonewall and on the National Park Service website entry on the Stonewall, trans references were removed.
Proper order! The place had been swathed in 'progress' flags, the history of the Stonewall Riots had been rewritten, completely ahistorically since 'transgender' wasn't invented till after the 1969 riots.
As PPs have pointed out, they retrospectively 'transed' the gay drag queens who played a big role in the riots, and Stormé, the lesbian drag king who, according to one version of the Stonewall mythology, started the whole thing.
Who knows who did, but one thing is certain: it was not transpeople!
A typical example of TRAs brazenly appropriating lesbian and gay history.
It appears that the 'original' Pride flag, the rainbow one not the 'Progress' one, has also been removed from the flagpole at the Stonewall site, something about only flying the national flag at National Park sites or something..