The US border agents aren't likely to deny anyone solely for having a Russian stamp in their passport.
It may raise questions, like with any travel to any country of 'interest' or just out curiosity. They may ask what the reason for travel there was, or who you interacted with.
However, if your reasons for travel are all legitimate, and you fulfill the conditions for entry into the US, you're unlikely to run into more than a couple of rudimentary questions. I've technically visited Russia 3 times, and have been in the USA 5 times since, and had no questions. Not even questioned about my time in Cuba. My Colombia stamp caused me more questions, but even that was fine eventually.