Welcome Shukuchi,
To answer your question, I don’t think it’s any less ethical than cosmetics, sales/dating techniques. Pheromones can in no way coerce someone to act against their will, they can only enhance or amplify what is already present.
If social pheromones are used, the person(s) targeted will open up to you but they won’t perform out of character. An easy example: if you’re selling strawberries and you’re using a sure-fire combo that gets people talk to you and usually leads to sales, you might get a lengthy conversation with a customer who is allergic to them but the person won’t buy strawberries all the same.
If you hadn’t been using pheromones, they’d have perhaps not stopped by for a chat but their usual behaviour of “avoid strawberries, they’re dangerous for me” won’t have changed.
You might want to check out this thread What pheromones can and can't do: realistic expectations for newcomers for a more in-depth exposure of what I mean.