I'm pretty confused what is the reason for this. Supporting blockchain on one hand and banning them on the other hand, well I guess only time will tell what their real attitude is...
The only thing I can think of is the issue of blurred lines or ambiguous services that might be pretending to just be blockchain related, but are in fact related to ICOs/token/crypto, so instead of sorting through them they have just banned it all together. Who knows. Taobao does have a lot of sketchy stuff on it though, to be fair.