I mean the ethical rules; the code of conduct many people seem to comform to.
Which is also what they hide behind whenever they have no reasoning to their school of thought. "Why wouldn't I do this?" "Because it's just wrong man!!"
Nothing is "just wrong" and everything social depends on the situation. This includes the relationship between a tulpa and a host. Even if a host makes a tulpa only for sex, if they are really sapient and dislike their existence, the sheer attention the host would give them while living out their fantasies would eventually leave them parallel enough to be able to resist whatever the host wants to do. And tulpas that aren't very independent seem to agree with their host often, so in the early stages of sentience, it probably wouldn't hurt them too much.
Either way; your head, your decisions. Being selective about the advice you give is fine, but once someone has already done something, the best you can do is tell them you disagree. Telling someone exactly what to do is always wrong in this practice.
The way I see it, it can easily lead to trouble that can be prevented. Sure, if the tupper isn't even sapient yet, I can't really argue about how you treat them. It's hard to say if the tulpa is sapient or not in some cases, though, so you (not talking about you personally) could do some nasty things to a sapient tupper thinking it's not sapient. But overall, doing what you want to non-sapient wannabe-tuppers doesn't matter.
However, let's talk about the actually sapient tuppers. Let's say they can and will resist. But first of all, the tulpa might feel bad that they're not what the host wanted. That can be very difficult for some and isn't going to get better unless the host accepts the tulpa or the tulpa becomes what the host wants, but that probably won't make the tupper feel too good.
But let's now assume the tulpa we're talking about is a STRONG, INDEPENDENT TUPPER WHO NEEDS NO HOST, who is happy with who they grew up to be and doesn't want to change, and doesn't really care what the host thinks or resists and doesn't let the host have his or her way with them. Crisis averted, host can't do anything to tulpa. Except the host is the only link to the real, physical world the tulpa has. What if they want to talk with someone outside the body, what if they want to use the body, what if they want to do something that requires it? It would be pretty difficult to do if the host and tulpa weren't in a good relationship. Impossible, even, if they dislike each other and aren't going to accept the other until they do what they want. Seeing that I have a tulpa who is really interested in the physical world, it would be very difficult to him if he wasn't allowed to have that option due to our shaky relationship. And well, as a host, I wouldn't want to force my tulpa to live a life like that. Nor would I want to live a life like that if I were a tulpa. So I guess I'll go the moralfag route of "treat others how you'd want yourself to be treated" or someshit.
Could the host learn that they can't treat their tulpa like shit and should accept them even if they didn't turn out exactly how they wanted? Sure, they could. But I think it would be easier and safer for everyone if they learned it before they started forcing a tulpa. The simple question of "can I allow the tulpa to be who they want to be?" would already go far. This is something I definitely think many starting tulpamancers should ask themselves. After all, if you don't want a being that is shaped by many things and often ends up quite different from what you thought, maybe you shouldn't make a tulpa.
Also, Fede, just posting that image doesn't really do anything. You don't explain what you mean with it to others, so it's pretty useless and brings nothing to the conversation. I suggest you explain yourself or else it ends up being something pretty spammy.