Having foreign investors can be a bit of an annoyance.  If you send the secret police to their offices to demand all the personal details of their clients, there is a possibility they will refuse, and cite international law and privacy rights or some such (take, for example, the Global Network Initiative).  They might not even give you what you want even if you threaten to strip them of their business license. 

When it comes to something as important as monitoring internet activity, it seems safer to just leave that in the hands of Russian companies.

From the WSJ:

The Communications Ministry is working up “security criteria” to determine where foreign ownership might be restricted, a spokeswoman said Thursday. Russian law already requires government permission for significant foreign investment in publications with daily circulation over one million. Several major Russian sites have larger audiences, she said.