I think TAG garner the snobbery around them because they sell, sell well and are popular that's pretty much it. They're a go to name in the general public's mind as a "luxury" brand. I'd bet good money that in a straw poll in most places in the world TAG would be comfortably ahead of Omega, never mind any of the others. Rolex would be only one with bigger brand recognition IMHO. Some would argue they went through a period of in the moment fashion that looks awkward now, but show me a watch brand that hasn't.* Others would argue they used low end movements, but again show me any of the main names that haven't. Even Patek was firing out "fashion watches" covered in bling and powered by a quartz movement.
The fact is we all buy into marketing and history(real, fluffed up, or imagined) and "authenticity" and make our choices accordingly. In this TAG Heuer aren't outliers who push it more than anyone else, in fact do it less than many** so I don't really see why they get the level of stick they get.
I say this as someone who isn't that enamoured with TAG offerings. I have one vintage Heuer and I wouldn't mind a couple of others. TAGs not so much, but it's a personal aesthetic thing with me. I just don't "get" their designs in general and wouldn't if they had another name on the dial.
*including Rolex whose design rate is positively glacial, dull even. Then again that's part of their appeal to many I'd imagine. Like Porsche, a slow evolution that gets the aficionados hot under the collar over tiny changes.
** Panerai is an almost entirely "made up" brand. Lange disappeared from view for over 40 years and they'd be considered beyond reproach among many WIS. Omega regularly puff up their history, sometimes to a farcical level(and even shill bid on high end auctions to pump up the brand). The list is long.