The issue here is companies didn't treat Milner et al as an extension of the Russian state. They treated them as private individuals who made money in Russia. The difference is night and day. The latter want to make money like other investors. The former may want things other than money. Transparency allows one to be wary about suspicious requests, requests which may not seem suspicious without context.
Disclaimer: I am not a lawyer. This is not legal advice. Speak to a lawyer before accepting, or making, investments.