"However, Raja Sahib wasn't done yet and he joined the Bhutto Government. Zulfikar Ali Bhutto made him Minister of Minority Affairs and Tourism in his Cabinet. Bhutto also offered the Presidency of Pakistan to Raja Tridev Roy. This was a great opportunity but it came with a rider. According to the new Constitution of Pakistan, only a Muslim could become the President of Pakistan. This wasn't acceptable to the erstwhile Raja Sahib of the Chakmas. So, after giving up the kingship of the Chakmas, Raja Sahib declined the Presidency of Pakistan".
Bhutto didn't want him to convert.
Where does it say that?
The Constitution of Pakistan is clear on the religious status of the President ( which I disagree with) .
The option of becoming the President with full political support was open, with the mandatory conditions which Raja Tridibh Roy was aware of.
Bhutto was not a religious bigot.
He liked his "chota peg" in the evening.
Let's get back to why the BSF shoots mostly Bangladeshi Muslims . Few if any Chakmas have been shot trying to cross over into India.