I can't see the Latvians (or Estinians and Lithunians) being that bothered about the Russian passport holders. All three hate the Russians for the ill-treatment post-WW2.
In Estonia, unless the Russian passport holder is prepared to jump various hurdles such as learning Estonian, they have no choice but to retain a Russian passport - like it or not.
As for the "Worlds Least Respected Airline" aka Ryanair - it's no doubt a querk with the cheap IT deal they got which prevents them from operating the Online Check-in for Russian passport holders.