I think other countries can also route through Russian ISPs to attack elsewhere. No long ago the US shutdown the North Korean internet for several hours (in retaliation for their attack on Japanese company Sony), by hacking through Chinese ISPs, since the North Korea's internet is only through China. So it's entirely possible and has been done before. There may also be foreigners in Russia using ISPs there to hack other countries.
I wouldn't trust ISP addresses to determine who the attackers are. After all, IP addresses are furnished by the routers of sender at each hop, per IP protocol guideline, like the address a sender prints on the envelope of a letter. Both the hardware router and software can be changed to provide false information. A sophisticated attacker can even design their own router with builtin back-doors to defeat the tracking protocol. This is not high tech nowadays.
Only unsophisticated attackers write their real address on the envelops.
Actually the only sure way to know where the attack comes from is through real intelligence. For example, the US knows certain attacks came from certain China military org because they have themselves hacked into the Chinese military computers, located the very building where the attackers worked, AND actually planted surveillance cameras in that office to actually view the attacks taking place. One "insider" joked that if the Chinese were daring enough people to attack the US sites, at least they should dress respectfully, and not wear their pajamas while doing it! I watched a China Forum (American) interview on Youtube that talked about how this is done. The moral is that everybody attacks, the less sophisticated ones get caught and exposed.
Personally I think if there's a government interested in our BS forum, that would most likely be our own government. If it's an individual or a private org, then it doesn't matter what country they operate from. There're sneaky people every where.