The Italian issued an official statement in response to an open letter titled "Selection Manifesto 12" published on Zenit fan website Landscrona on Monday which detailed its "principles for selection" and preferred criteria for future signings.
In a section headed "The mentality of the human", the letter published on landscrona.ru read: "We object to representatives of sexual minorities playing for Zenit."
Zenit remain the only club in the Russian top flight to have never signed an African player.
The letter continued: "We are not racists and for us, the lack of black players at Zenit is only an important tradition, which emphasises the identity of the club and nothing more.
"Zenit has its own identity in the world of football, along with a number of football clubs that have retained their own identity.
"As the most northern club of the major European cities, we have never been associated with Africa, South America or Australia and Oceania.
"We have absolutely nothing against the people of these and any other continent. But now black players are being imposed on Zenit almost by force.
"We only want players from other brotherly Slav nations, such as Ukraine and Belarus as well as from the Baltic states and Scandinavia. We have the same mentality and historical and cultural background as these nations."
Without referring directly to the statement, Zenit boss Spalletti told fc-zenit.ru: "Tolerance for me is the ability to understand and accept differences.
"Furthermore, being tolerant means that you fight against any kind of stupidity.
"I can personally assure you that I will do everything I can to help those who seek to explain what tolerance is, and the need to respect other cultures and traditions.
"The team has gathered players from different countries and ethnic groups who work together to achieve a common goal. Their combined efforts bring tangible results."