Medieval fiery rivalry of Catholic and Orthodox faiths that was sparked by Polish–Muscovite War back in 1600’s still lives in back of the minds of modern Eastern Slavic people. This was from the Maslenitsa weeks, one of the older surviving Slavic holidays that has pagan roots among Slavic populations in Central and Eastern Europe. However this beautiful tradition was ruined for some (especially Catholic tourists that were present at the location) by making the effigy a Catholic Church. Was that a pretty bad PR? Probably, the artist sincerely apologizes and explain it was not planed to burn churches but just to make Gothic architecture effigy, but still many feel it has a different message behind (you know the usual one, Slavs provoking Slavs).
In history during this time it was usual to burn an effigy representing the Slavic goddess of winter Morana, it was an act where they burn her to banish evil and deadly winter away. How it shifted onto burning religious Churches on a Christian holiday it is unknown, maybe next year they’ll burn a synagogue or mosque too, obviously effigy game has stepped up.
Few days later Russian Orthodox church criticized the action and demanded that its organizers be found. The author of the idea for the burning of the cathedral is the artist Nikolai Polissky.