Because a lie told often enough becomes true.
Realistically, every useful idiot is afraid to say they don't know if a Chinese company is a spy network because it's sooooooooo obvious even asking for proof makes them look stupid.
Ironically, not asking for proof is what makes us stupid.
If something is "so obviously true" yet nobody can provide evidence for it when asked, it's probably the propaganda mill doing its job.
Bad people are allowed to do bad things as long as they have the money for it.