Anal Intercourse is a Dangerous Hobby

[Mr.wizard]

So no simply bringing up the subject isn't the cause of hostility .The motivations of religious types bringing it up can invoke hostility as often they have ulterior motives for doing so

Your getting push back because your saying, "anal sex is harmful"

Thanks Mr.wizard for confirming the facts. Im getting push back because im telling the truth, not because of any paranoid notions of religious motivations.

So what if someone did have religious motivations. Doesn't change the facts.

it has been pointed out to you that while anal sex can be harmful it doesn't mean that it's always harmful, it's not like every time you have anal sex you get an STD

Apart from contracting STDs there are many other medical risks to anal sex. These risks affect the person being penetrated. 
They can range from a laceration or bleeding to death from anal cancer. Here are some of the medical problems that are caused by anal sex.

perineal cellulitis
enteric fistulae and faecal incontinence
severe perineal laceration
complete anal sphincter complex disruption
anal sphincter injuries
anal incontinence
irritable bowel syndrome
random defaecation
faecal soiling
pelvic congestion
anal sacrococcygeal
fecal peritonitis, 
intraperitoneal peritonitis
rectal perforation
constipation
hemorrhoids
rectal bleeding
abdominal sepsis
blood sepsis
rectal douching
anal fissure
anal fistulas
abscesses
explosion of the rectum and colon
rectal prolapse
anal protrusion
anal cancer 

Just to name a few. 
So while it is not "always harmful" a person becomes morally responsible when it does cause harm.

Of course the people who are having anal sex are responsible if something goes wrong, who the hell else would be responsible? The same would go for vaginal sex and oral sex. But if two people are having anal sex and they both like it and they aren't experiencing any health concerns where is the harm?

Your religious motivations about anal sex matter because I believe you think that if you can show anal sex is harmful then you can say that homosexuality is harmful.