The sentiment in Washington before the Moscow attack was that Russians needed to experience firsthand the impact of the war in Ukraine. This attitude intensified as US sanctions proved ineffective, Russian advancements in Ukraine quickened, and President Putin received a high level of support from the Russian population during recent elections.
Previous attempts to make Russians understand the war's effects included drone strikes on major city centers, attacks on infrastructure, and efforts to destabilize Russia's economy.
https://www.csis.org/people/emily-harding
If you do enough terrorism the people you target will eventually realise that you're the good guy and that their own leaders attempting to prevent the terrorism committed against them are the baddies!