It seems that someone recently added a tag called frostcycling. It doesn't have usage guidance at the time of writing. Looking at the list of questions, they appear to be not distinct from the winter tag. Going off my memory, this question by @Sam may be the first question tagged as frostcycling, and it's the first one I remember seeing the phrase "frostcycling" in.
I am not sure that frostcycling is a term in common usage, at least in English in the West. Policing language that you don’t like is ultimately futile, as terms will eventually catch on if enough people find them meaningful. However, Googling “frostcycling” doesn't appear to reveal any hits per se aside from the question I linked above. In fact, many of those hits contain "frostbike" instead. One of those hits is a book titled (emphasis mine) "Frostbike: the Joy, Numbness, and Pain of Winter Cycling". There are more hits for a recurring event called Frostbike organized by Quality Bicycle Parts (a massive US distributor of bike components that also owns several fat bike brands).
I propose that frostcycling be deleted and merged with the winter tag, unless we can find evidence that it's a phrase used by at least a group of cyclists and we can distinguish it from the winter tag.