Took me a while to read all this.
Yes it does seem like this community does like to argue terms/labels or what-ever.
As some one who fully transitioned from 1974-1977, and consider myself to be fully a woman first, a MtF Post-Op TS 2nd.
Back in my day, the DSM II, only describes the condition of Transvestite. Not sure when name CD mostly replaced TV as a nicer name. TS did not get put in until DSM III in the 80s I believe. TS was a name that Dr Harry Benjamin, see his book "The Transsexual Revolution", and others came up with to describe people that would fully transition.
I had heard of the name TG mainly from some in the TV community to describe someone who lived as a "woman" but did not transition.
In the 70s other than a Court Legal Name change, There were NO legal rights for TV or TS, and as with the Gay/Lesbian communities could be locked up in jails.
My partner and I left the fragmented community of Gay/Lesbian/TS/TV behind in 1983. Don't know when the whole LGBT(QIA+) came about to describe an actual related community, I think it was for political reasons as someone said.
In 2014 my partner died, and I decided to find out what all had changed in that time.
As some have said, to the general public TG=TS. So much for it being an umbrella term.
What I heard later was many in the TS community like TG because it took the Sex part out and put Gender in. Plus many would find TS objectionable because of the Porn Industry using it for their own use.
I argue that to use the cis-gender terms of Gay/Lesbian/BI to be so confusing in the TG/CD/TS world. I'm not even sure we need to keep using those names, except people like to proclaim, "I'm straight" so I must be OK. The scientific community has much better names to describe sexual preferences/attractions.
"Androphilia and Gynephilia are terms used in behavioral science to describe sexual orientation, as an alternative to a gender binary homosexual and heterosexual conceptualization. Androphilia describes sexual attraction to men or masculinity; Gynephilia describes the sexual attraction to women or femininity."
And my favorite that a lot have a problem with.
"Autogynephilia (AGP) is defined as a male's propensity to be sexually aroused by the thought of himself as a female. It is the paraphilia that is theorized to underlie transvestism and some forms of male-to-female (MtF) transsexualism."
I have seen people use names like "Male Lesbian" "Trans Dykes" or "NB-TS" or others that make me question what other terms/labels we can come up with.
If people want to call themselves whatever they want to, GO ahead but it may be confusing to many around you.
If you want to see some interesting discussions, look in the TG/Non-Binary area.
In the TS area, we can have Pre- Post- Non- (transition or Op), for a variety of reasons. And transition can be Social or Medical (HRT) or Surgical. But all are still considered TG/TS.
These are just some of my quick learning in my 66 year existence and 40 years Post SRS.