The post was simply a reminder that there are outher religions whose devout adherents have contrary beliefs to Christians and most of which would think it odd that Christianity claims three gods in one.
Also, many Hindus do not agree with this number. Some say there is only one God, while some say there are 33 gods only. The reason behind this confusion is that the different scriptures give different numbers.
Source:
Brihandaranyaka Upanishad (3.9.1):
The same question was asked by Vidagdha to Sage Yajnavalkya, and he gave the following answer:
Then Vidagdha, the son of Sakala, asked him: “How many gods are there, Yajnavalkya?
Yajnavalkya said, “As many as are indicated in the Nivid of the Visvadevas – 300 and 3003.”
“Very well,” said Sakalya. “How many gods exactly are there, Yajnavalkya?”
“Thirty-three.”
“Very well,” said Sakalya. “How many gods exactly are there, Yajnavalkya?”
“Six.”
“Very well,” said Sakalya. “How many gods exactly are there, Yajnavalkya?”
“Three.”
“Very well,” said Sakalya. “How many gods exactly are there, Yajnavalkya?”
“Two.”
“Very well,” said Sakalya. “How many gods exactly are there, Yajnavalkya?”
“One-and-a-half.”
“Very well,” said Sakalya. “How many gods exactly are there, Yajnavalkya?”
“One.”
“Very good,” said Sakalya, and he asked: “Which are those 303 and those 3003?”
Yajnavalkya said: “There are only 33 gods. These others are but manifestations of them.”
“Which are those thirty-threes?”
“The eight Vasus, the eleven Rudras, and the twelve Adityas–these are thirty-one, and Indra and Prajapati make up the thirty-three.’
Therefore, per the Brihandryaka Upanishad, there are a total of 3003 gods, but they are manifestations of 33 gods.