It is sometimes suggested that Islamic countries are oppressive. I seek here to test whether this suggestion has any basis in fact, and whether such associations can be found for other religions.
I have looked at the freedom scores of countries as assessed by Freedom House and whether there is any apparent relationship with the religions of those countries as documented on Wikipedia.
Freedom House scores countries on a scale of 0 (least free) to 100 (most free).
The Wikipedia article breaks countries down by religion in seven categories, which it calls Christian, Islam[ic], Irreligion (atheism), Hindu, Buddhist, Folk Religion, Other Religion and Jewish. The accuracy of these classification might reasonably be questioned – the appear to be cultural designations rather a measure of active faith – but for the purposes of this study they are used as provided.
For each religion, I have plotted the freedom scores against percentage adherence to that religion for all counties for which the data was available, with a line of best fit and a confidence region.
The graphs below plot freedom scores against percentage of adherents to religions, with each point representing a country, the total country population displayed as the size of the point and the various continents in different colours.
Working our way through the columns in the Wikipedia table:
There is a positive correlation between Freedom Score and Christianity, although there are non-Christian countries with high freedom scores (Mongolia, Northern Cyprus, the Czech Republic) and (at least nominally) Christian countries with low ones (Central African Republic, Democratic Republic of the Congo, Equatorial Guinea, Burundi, Swaziland).
There is a negative correlation between Freedom Score and Islam, although there are non-Muslim countries with low scores (Central African Republic, Equatorial Guinea, South Sudan, North Korea, and many others) and Muslim countries with reasonable ones (Northern Cyprus, Senegal).
There is a positive correlation between Freedom Score and what Wikipedia calls Irreligion, though there are few countries where Irreligion is very high (the Czech Republic being the exception) and this creates significant uncertainty in the relationship.
There are only two countries where Hinduism is common (India and Nepal), so the data do not provide useful evidence about its relationship to Freedom Score (we can draw a horizontal line in the grey area).
There are likewise few countries where Buddhism is common (Burma, Cambodia, Thailand), so the meaning of the data is again unclear.
We see the same issue with Folk Religion – no data at the high end (although what we can see doesn’t look good).
Likewise, there is little data for Other Religion,
or Judaism (with Israel out on its own).
So what can we conclude from this, and what can’t we conclude?
Clearly, there does appear to be a real basis for the perception that Islamic societies are oppressive, while Christian societies are not and societies with a high proportion of atheists are not.
It does not follow that Islam causes oppression – oppression could lead people to Islam (though it’s not clear how) or some other, confounding, characteristic could both cause oppression and lead people to Islam (though it’s not clear what). But the most obvious explanation may also be true. Similarly, it may be that atheism promotes freedom, but could also be that free societies are the ones that allow people to identify openly as atheists. Studies using whole-of-population statistics like this one cannot answer these questions.
It does not follow that the Muslims are the oppressors, though this is the most obvious explanation and may well be true. An examination of Islamic history may help clarify whether this is plausible. Similarly, it does not follow that Christians or atheists champion human rights, though they may.
It could be argued that Islamic societies sacrifice freedom in the pursuit of some more important good. It is not clear what this might be, but the reader is invited to offer suggestions. I intend to address such possibilities in future investigations.
The study shows an association between Freedom Score and Islam, which is negative.
The study shows an association between Freedom Score and Christianity, which is positive.
The study shows an association between Freedom Score and Atheism, which is positive, though less clearly so.
The data are not useful for examining other religions, so I will not do so in future investigations.
 See, for example, https://en.wikipedia.org/wiki/Human_rights_in_Muslim-majority_countries.