TERFs falling out of favour with the "actual leftist subs" is also a relatively new thing... they used to be strongly TERF apologist at the very least, if not actively and heavily promoting them in the case of several of the more feminist-aligned ones. Think last few years. This isn't just a Reddit thing either; questioning their ties to the UK's main left-wing political party (which has actually influenced our laws for the worse) used to be way outside the range of acceptable leftism, but has suddenly become a controversial hot topic in the last few months.