Please be remindful that the statement is that "all companies are branch of military"...
And to be precise, "People's Liberation Army owns and runs many businesses" this is almost certainly a misunderstanding of the organizing structure.
Mr Deng Xiaoping deliberately not disallowing military involving business activities [1], in part it's because the military is starved from support and resources, and they need some form of self-sustaining to maintain the basic infrastructure, especially ensure the continuation of the talent development relevant to high-end military capability.
That was banned in Jiang Zeming's rule [2]. In part, just like the purge done by Xi, was because military with its own finanical sources will become a plitical risk to the party head.
Today, there isn't any military owned business, officially. There are state-owned military equipment companies and research institutes. But their relationship with military is not too different from Locke-martin & US government & US military. (I mean, US system works better, right? Then CCP will happy to copy...)
Of course, there could be grey areas, and exceptions. But it should be common sense, here I repeat, military personnel cannot have financial support in their own control, that threatens the political leaders' authority.
If you can name one "active duty officers serving as executives", I'll be very surprised...
[1] http://congressionalresearch.com/98-197/document.php?study=c...
[2] http://www.globaltimes.cn/content/981596.shtml
[3] https://www.businessinsider.com/xi-tells-chinas-military-to-...