This is quite true. About a decade ago GFW was a simple IDS that occasionally sent RST packets down the pipes. Nowadays it's much more complicated. I've witness

This is quite true. About a decade ago GFW was a simple IDS that occasionally sent RST packets down the pipes. Nowadays it's much more complicated. I've witnessed the GFW upgrade in process several times in which they default to drop every cross border connection over port 80 but allow everything else through, then gradually going back to normal one route at a time. However I'm not sure if the GFW is the blame for every case of passive throttling. Certain provinces have it better than others and there is no obvious pattern, especially CMCC which constantly have issues connecting to domestic services, but otherwise has very little throttling once you know how to get past the GFW. The same cannot be said for other providers which throttles home users extra hard so their capacity can be sold to business customers.