Yes, OP did not specifically focus on anal sex, but they did mention it in the post even if their focus was mainly on other kinks they claimed are unhealthy.
Those who are against anal sex argue the exact same things this OP does, they say "anal sex is unhealthy. Imagine if you're in a place where there are no lubes and condoms to reduce the risk of higher STD and STI transmission rate via anal sex. Anal sex is that dangerous, so even if two or more people consent to engaging in anal sex, they should be stopped from and shamed for doing so"
We can counter with "what about dangerous sports that people consent to? If you are not going to ban them then you shouldn't ban anal sex".
But those who are against anal sex can argue the following just like that OP (change OP's words in the comments and it becomes exactly what they argue):
We should definitely be open to stigmatizing an outlawing combat sports or sports that lead to excessive damage. There has been a cultural shift in the US recently of people not allowing kids to participate in sports like football and cheerleading. 2 Presidents have now said they wouldn't let kids participate in those sports. That is a cultural shift, not a legal one, and we consider it to be good. From the cultural shift, we can change laws, and then outlaw sports which are dangerous and too risky for everyone, not just kids.
Anal sex is riskier than vaginal and oral sex. It is by far the riskiest sex in terms of STD and STI transmission. Just as things such as self-mutilation, a kink some people have which has an adverse effect on someone with their consent, are shamed and made illegal, anal sex should be stigmatized, shamed and made illegal.
As a society, we have stigmatized and in many cases outlawed many activities, such as "self-harm". Eventhough the individuals cutting themselves consent to the cutting we banned and stigmatized "self-harm". We banned "suicide" eventhough the individuals consent to "committing suicide". We banned self-mutilation eventhough the individuals consent to cutting their body parts. We banned the usage of many drugs eventhough the individuals doing the drugs consent to it.
We have stigmatized and banned all these things, because consent does not matter, there is no such a thing as "my body, my choice" or else "suicide", "self-mutilation", "self-harm", etc would not be illegal in most countries. One should not be allowed to do what is damaging to them even if they claim to want it and agree to it.
And since anal sex is unhealthy, and damaging, it should be stigmatized, shamed and made illegal.
If not completely illegal for everyone, anal sex should be made illegal for anyone who is under a certain age such as 18-20. Just as there are laws regulating the usage of guns, and playing certain dangerous sports are not allowed for certain ages until individuals learn to safely play the particular sports, anal sex should be illegal for everyone under a certain age such as 18-20 until everyone knows how to safely engage in anal sex.
You think this "violates freedom", but a society whose cultural ideal is simply "maximum personal freedom" is not one in which we wish to participate. That is not the society that we have EVER had, either.
A society that sees someone cutting their own hand off and says "Huh, don't care about that," is, at the very least, abnormal. I wouldn't want to live in a society with that little care for other human beings.
Of course we are advocating for telling other people what they should and should not do.
We do this all the time. We tell people not to "commit suicide", not to "self-harm", not to rape, not to steal, not to intentionally piss their pants in public.
All these things carry social stigma with them.
People ostracize those who smell bad, piss their pants, steal, etc. It's a perfectly normal human attitude to tell others what to do and what not to do. It's not a bad thing.
We make choices on a daily basis, constantly. We tell other people how they should act, constantly. It's called setting boundaries. That's what eventually turns into cultural and social norms, stigmas, and taboos. Personal opinions turn into cultural attitudes which turn into social norms. It's a long process, but that's how it happens.
And societies do not start out with maximum personal freedom. That's not a society, that's the state of nature (which never existed anyway). A society is formed when a group of people come together and decide to live together under certain cultural, legal, moral, etc. standards. Look at the founding of the U.S., for example. There were already existing cultural, societal, and legal standards before any semblance of a constitution was written.
Does anyone have any arguments against all that?