Because the US attacks their rival citizens, and not the rival governments. Take the case of Russia for example.
After US invaded Afghanistan in 2001, they legalized the production of Opium poppy in Central and South Afghanistan. Then they helped the smugglers in exporting the hash and heroin to Iran and Russia, so that the young generation in those countries become hooked to the drugs. Afghan drugs have killed millions of young Russians. In Iran also, hundreds of thousands of young people have died.
So, if I were the Russian president, and if my armed forces were as powerful as the American ones, I'll be definitely targeting the American civilian population. Tit for tat.