Revolting sex based cults have existed since antiquity (For example the Cult of Dionysus or that Etruscan tomb with art depicting a BDSM themed threesome).
The things that make the trans cult unique and the fastest growing in recent history can be summarized:
1: While previously (most) cults manifested in the upper echelons of society our civilization gives them the insurance/taxpayer dollars needed to partake in the cult, therefore making it so all but the most downtrodden can join the trans cult if they are converted.
2: trans people, most notably trans women, are worshipped by the culture at large and are allowed to do just about anything they want to those who ruin the party by not validating their fetish. This attracts power hungry narcissists who want to be worshipped by those around them and able play the hero by assaulting anyone labelled a blasphemer, or in this case, transphobes.
3: It is being actively encouraged by the ruling caste. Sure there were sex based cults in the past that were open to the public but those were almost always fringe groups that could have been ignored by the rest of the citizenry should they want to do so. This meanwhile is actively recruiting new members through a relentless propoganda campaign on a scale no historical society could have ever imagined.
In addition this is largely linked to the rise of porn. PORN. Porn use used to be shamed by nearly everyone, until the internet ushered in an era of free instant porn in the privacy of one’s own home. Religion becoming less popular in the west is also relevant. I’m not saying any religion is true, the point is the west in general, and USA specifically are highly individualist cultures. Religious meetings gave people community. People left religions (good!) but the community was not replaced with anything.
Humans are communal by nature. We crave belonging and a group to be a part of. This is why so much TRA rhetoric resembles religion, namely Christianity (don’t ask questions, trans women gave you rights=Jesus died for your sins, etc).
TRAs have replaced traditional religion in their lives with this cult, which is why it is called a cult in the first place. Had they been a part of an alternate system most of them would never have considered castrating themselves while crossdressing to fight off encroaching feelings of existential dread.