I have seen some pretty vile people online who somehow believe the victims deserved to die on account of them being Russian and therefore they made the supremely logical mental leap that somehow Russian civilians are responsible for the actions of their government concerning Ukraine and should be punished accordingly.
ISIS claimed responsibility, yet I have a hunch they've claimed responsibility for many attacks over the years that they didn't originally do in order to make themselves look more powerful to Western audiences. Kinda like the kid who steals your answers to the homework and writes it off as their own to make themselves look smarter. As usual the knee-jerk reaction of the Russian government was to blame Ukraine for facilitating the attack. Only time will tell if this statement has even a morsel of truth to it.
Russia vetoed the draft resolution for a US-endorsed Gaza ceasefire the same day. Wouldn't surprise me if the militants in question may have partially carried out the attacks in revenge for the Russian government's veto, and Russia's continued offensive against ISIS in Kurdish areas. Perhaps Russia may now learn, alongside a spate of localised partisan activites in the Kursk/Belgorod areas, that you can't wage wars on foreign soil and not expect the conflict to reach inside your own borders at some point.
Honestly it seems that political/social opinions are becoming more and more polarised to the extent we now have a pretty loud minority of people endorsing some form of collective punishment to Russian civilians for the actions of a leader that they didn't democratically elect. The majority of Russians are de-politicised - they didn't choose for the invasion of Ukraine to happen.