There is a huge, critically important difference between "things people should not do" and "things people should not be allowed to do." Blurring the distinction between those categories happens in every part of the ideological map, and every time, it's lowkey horrifying.
The second you get that word allowed in there (or any variant on the concept) you've suddenly brought in a whole truckload of presumptions around detection, determination, and enforcement that don't exist when the statement is simply shouldn't do it. When you say shouldn't be allowed to, suddenly you're saying that an authority figure of some type, whether it's law enforcement, the justice system, an employment tribunal, a regulatory organization, or a group leader, should be empowered to determine the truth of whether the infraction has occurred or not and should have the power to leverage a penalty against transgressors.
And like, sometimes that's valid! I'm not saying that no action at all ever should be outlawed. What I am saying though is that we should carefully consider, in isolation from the question of whether or not a particular action should be done at all, is whether that action should be punishable.
You shouldn't be rude to random people on the street. Why? Cause you're inflicting hurt, however small and temporary, on people who have done nothing to you. You're increasing the negativity in the world for no reason. Okay, that's a fine concept. But when you turn it into you shouldn't be allowed to be rude to random people on the street, now we're in a horrible dystopia where there's Pleasantry Cops on the corner and if you don't smile at random passersby, you're in danger of getting arrested. That's horrific.
And even with more serious infractions. You shouldn't cheat on your partner. Okay. I think we can all generally agree on that! (Reminder that consensual polyamory or open relationships aren't cheating; cheating as a concept specifically entails breaking the agreements the relationship is founded upon.)
But in places in the world where infidelity is legally punishable, it's a weapon of state morality enforcement that 1) somehow mysteriously (ha) only gets leveraged against women, and 2) is very frequently used to further traumatize women who have been raped and dared to seek justice. And even if you posit that a state could potentially enact a ban on infidelity that is equitable and does not punish victims of sexual assault, you're still inviting state scrutiny into people's bedrooms and consensual sexual behavior, something that has never, not ever, in the history of the entire world, gone well.
That's all true, and still, cheating on a partner is bad and you shouldn't do it! But you should absolutely be allowed to do it because the alternative is so much worse.
And of course, flip side, there are certainly things that you indeed shouldn't be allowed to do. I am perfectly fine and comfortable with saying you shouldn't be allowed to murder people. It is reasonable that when someone has met a violent death, the state apparatus gets involved and starts digging into how that was done, by whom was it done, and why was it done. There's certainly ways that prohibitions on killing can be implemented inequitably, but it's generally recognized that preventing bloodshed and indiscriminate slaughter is a useful purpose of civil society and the implementation of the same is by and large more beneficial than harmful.
Taking the time to separate "should people do this" from "should people be allowed to do this" is critical to discussing public policy in any kind of meaningful way, and I encourage people to always ask these questions and consider them separately and independently of each other. What would disallowing X action entail? What are the boundaries of defining X action in a legally enforceable way?
The key takeaway, if anything, is that everything not prohibited is allowed, and the passive voice "be allowed" in saying people shouldn't be allowed to do that takes a massive sidestep around the questions of by whom and how would the thing be prohibited and punished. Don't let the sidestep simply happen. Tackle the questions face on. If a thing should be prohibited, what are the prevention and enforcement mechanisms? Are they fair? Are they worth it?