sorry what do you by mean diversity of thought, if you meant by the acceptance of something which goes against Islam then you are totally right about Islam. Islam is not here to conform to peoples needs you either follow the laws and teachings of Islam or don't, simple as that. i am not going to sugar coat Islam for you because Islam is of set laws that you need to adhere to. Islam is way living and if don't want that well you leave the religion. freedom of speech/expression can not fully be exercised or implemented so the notion that Freedom of speech/expression and Islam are against each other are somewhat true because when you adhere to laws and teaching of Islam which exercises some teaching which you are forbid to do such homosexuality, killing and etcMy question still remains.
And the answer is that Islam does not encourage diversity of thought as state sanctioned killing of apostates and extra-judicial killings of dissenters is common, and the former is exclusively criminalized in muslim countries.
Freedom of speech/expression is not yet an islamic concept, sadly.
Now, was that so hard to explain?