On September 6, 1991, a decree was issued "On the return of the historical name of St. Petersburg and change to name". In the early 90's, in the era of reforms, there was the …

Petrograd (St.Petersburg name during WWI and October Revolution) had the name of Peter the Great, so it was renamed after Lenin (and Revolution mainly occurred there and under his guidance, so it was very symbolic). Moscow always had a rather neutral name. But there were several attempts to change it.

In 1991, City Council conducted a referendum offering the citizens to chose between “St. Petersburg” and “Leningrad”. Only original name St. Petersburg was suggested as an alternative to then-current Leningrad. 54% voted in favor of St. Petersburg which was advertised as “historic” and “authentic”.

Landowner Peter C. Demons whose ancestors were from the then Tsarist St. Petersburg, at the time the seat of the Russian Empire was inclined to choose this name verbatim for the new city. 20 years later the former was renamed Petrograd following a bloody revolution and civil war by the bolsheviks (Soviets) until Stalin had it renamed again.

For the same reason that St. Petersburg, where your troll farm is located, doesn’t change it’s name. It’s inconvenient. Oh wait, your city did change it’s name. Wasn’t it Leningrad before? And before that, it was St. Petersburg? See - people don’t like changing the name. They changed it back. That’s why.