The sanctions involve the government not wanting anyone to be able to read things written by Russians. Shocking. Why, you might catch a nasty case of the ol' misinformation!
If the site is selling something, and the visitor buys something, then the visitor is "doing business". Reading text that is published at zero charge isn't "doing business".
At the ISP level, it is even clearer than at the individual level. The ISP is passing traffic through from an entity, based on a business relationship, either direct or transitive, with that entity.