The proof btw is the fact that some of Siteground’s servers are using banners that are only used by a specific set of companies in China...the “sinister 6” I once heard them called. Venus, TOP-SEC, SANGFOR, NSFOCUS, and Hillstone Networks were all formed in the early 1990’s (some under different names) by the MSS, the Ministry of State Security. It is like a combination of the CIA and the FBI. As for the last of the 6, that would fascinatingly need H3C, formed out of a partial merger between Huawei and 3Com.
All of these companies sell exclusively defensive firewall, DDOS and NG-WAF-like products. At one time there mission was more defensive, the Chinese were paranoid, rightly IMO, that they were running entirely on American software and thus very vulnerable (with the exception of the Titan Rain attack in 2003). However after the GFC in 2008, as hacking became more aggressive, China would start leveraging these firms for surveillance and DDOS on an extraordinary level. Now they have grown so bold as to do things that are frankly somewhat humorously obvious if the situation was not so serious and the political leadership of most countries devoid (purely due to birth years and what they were exposed to) technical experience.
EDIT: because the Alexa Top 1 Million is pretty well sanitized, best resource I recommend is a book from the Naval Institute Press that came out two weeks ago: https://www.usni.org/press/books/chinese-communist-espionage