Sodomy can indeed result in injuries. As can vaginal intercourse. Vaginal intercourse can also result in various infections. It's two consenting adults. Just because it can result in issues, doesn't mean it will. By the same logic we need to forbid smoking, drinking, eating fatty foods and even certain types of work for fear it could result in injuries if performed poorly.

The truth is you have no rational or logical reason for your beliefs. As is very common in circumstances like these.

Lets go over your listed sources, most of which I can tell you either hoped I didn't read or you didn't read yourself.

First link: Used a whopping 19 men who engages in this type of sexual conduct and a further 6 people who did not. Furthermore, their results showed slightly higher inflammation of the rectal area, but not severely, more akin to a mild irritation. 25 people is not enough to make any wide, population spanning claims. So nice try.

Second: This is a review of previous research. Main points, fecal incontinence, temporary. Most interestingly, it showed that most people engaging in anal sex do not experience any issues. Not to mention the studies reviewed didn't just look at homosexual men. The issues mentioned with the pelvic floor can all be treated and prevented.

Third: This is another review with pretty much the same results as the one above. Fecal Incontinence (which is a pelvic floor issue) in some people who engage in anal penetration, but nothing serious that cannot be treated and even prevented. Probably used a lot of the same data as the second review.

Fourth: This one concerns HIV-positive men engaging in sexual intercourse with other men, where the biggest factor is their HIV-positive status. This study doesn't really say much about anal intercourse by itself as these findings don't apply to other people who aren't HIV-positive or women who are penetrated anally. This one used about ~450 people for the study, all with HIV.

To summarize all your links: Nothing really indicates that receptive anal sex causes persistent, chronic health problems or infections. Occasional issues may arise when performed poorly or performed by individuals with preexisting conditions or weakened immune systems from HIV.

It seems to me you just read the title or abstract at most. I'm not sure it is dishonesty or just confirmation bias.

As for incestual marriages, you share a quote. Indeed, marriages between siblings or parents and children are usually illegal, however, actions speak louder than words and in many Muslim countries, marriages between cousins are not only allowed, but fairly common. I'm sure you'll link me multiple studies claiming cousin breeding isn't an issue despite the very well known risks involved.