Not only have transgender people not always been here - the concept and the word are recent - but they also rewrite history shamelessly to falsify the record.
Take the Stonewall Riots in NYC in 1969, taken as the starting point for the modern lesbian and gay movement - transpeople claim that it was started by 'transwomen'. A previous poster referenced Marsha P Johnson, who was a gay man, not a transwoman. The men who frequented the Stonewall Bar were men. Gay men. They went there to meet other men.
There was a 'drag' subculture there, and some of the gay men were drag performers, and wore make-up, and referred to each other as 'she', but they were not claiming to be women.
One legend has it that it was actually a lesbian, Stormé DeLarverie, who started the famous riots, which is about as far from a trans-identifying man as you can get! But whoever started the Stonewall Riots, one thing is sure: it was not a transwoman.
The trans movement co-opted the Stonewall Riots, and covered the actual bar with trans flags, which was deeply offensive to the lesbian and gay community for whom it was an important location.
[They have since been removed, I'm glad to say].
An even more shameless example was the photoshopping of a trans slogan onto the photo of the first lesbian and gay march in Ireland in 1983, which was in memory of a murdered gay man.
Apart from the obvious anachronism - 'transgender' didn't exist in 1983- the disrespect shown to the murdered man and his family and friends by hijacking this memorial event is disgusting.
I'm sure others can come up with examples of TRAs rewriting and falsifying history to put trans in where it never was, to try to back up the 'trans people have always been here' claim.
Adding the T to LGB has exacerbated this: anything or anybody lesbian, gay, or bisexual, even from centuries ago, is now anachronistically labelled 'LGBT.'
LGB✂T, ASAP, in the interests of historical accuracy, as well as everything else!