issue is that you have already made up your mind when you said “can you seriously see something made halal for us by Allah (SWT) and RasoolAllah (SAW) could harm us in any way?” and what you are trying to do by your analysis is to defend this statement with a preconceived notion…appreciate your religious passion but that is not the way you do research…if we go by your thesis, no need of ijtihad, ijmah or qiyas…just lakeer kay faqeer. Islam is far more progressive than what you think…
Dear pyash, I must say that you have been intellectually dishonest in your analysis. Of course, we all know that if a pakistani marries a german girl and if cousin marriages occur in that family in next generation, it would be of a less to no problem … so YES one can say that the concept of cousin marriage is not the problem in itself rather we shd focus on marrying in other races but of-course if you continue practicing cousin marriage (even second or third cousin marriages) over a longer period in Pakistani-german racial arrangement, serious problems will start to emerge. There is a lot of scientific data to prove that.
The point i am trying to make is that YES first cousins related via a single channel are obviously far less at risk than those whose ancestors have** interwoven DNA** for 300 years (the Amish) or 1,300 years (Islam entered Pakistan in 712 AD.) …
… now lets get to the point that you are making in relation to “non-cousin marriages giving birth to babies with health issues in inida/pakistan at a higher rate”…this is not a relevant point as this group also shares a serious interwoven DNA history in a flat genetical society via cousin marriages at some point in their lineage history…maybe not at the point of survey but definitely at some point in the history.
let me give you an example…say i ama rajput muslim and i marry to a rajput muslim girl whose family has no history of marrying my family for last 50 years but i can guarantee you that in last 1000 years these 2 rajput muslim familes had married to each other for many many generations because rajputs pride in their ancestral superiority plus they dont want the land to go out of the family…and hence partners from these rajput families carried a defect in any of the genes associated with some form of illness, which can then show up even 6 generations later…same is true abt jats and syeds…you see my point?and who allowed them?..Islam who allowed such marriages.
so what isthe solution…Societies like USA are racially diverse, but those who have relatively flat racial profiles genetically like pakistan/india prohibit at minimum the cousin marriage …Ethiopia appears the most prohibitive: it bans marriage between relatives out to 6th cousins. South Korea bans out to 3rd cousins; Taiwan and The Philippines ban first cousins, as does China, ever since it’s 1981 Marriage Act. South America is also very very strict about the cousin marriages.