No You misunderstand. Sawada is just a convenient tool for her to get her kicks off. He's a literal no body. A loser of losers. Never changing, never improving. Even stating he loves her, but never improving for her, while fmc literally goes out of her way to look good for him. What a waste. Realistically this relationship will not last long. The only thing keeping her with him is the bondage stuff, and that's all her. He's just along for the ride, because he's a convenient outlet for her lust. He needs to improve himself if he ever hopes to keep her till death do us part. Realistically people should have taken notice of her inside school, and outside. People talk shit about him, because he's literal garbage. Standing next to a beautiful flower. He needs to be aware of himself, and aware of those around him, or else realistically she will be stolen from him. The moment someone better than him shows up. Ps there's a reason why this manga is called unattainable flowers twisted bloom. She's twisted, and he knows her secret, because he caught her red handed in the act.
If he really was just a tool for her to get her kicks off like you say, she would have to give him commands for her bondage stuff (since you said it's all her). Yet, she states times and times again that he knows what she wants without needing to tell him anything. That's, my dude, a bond of trust and understanding, a special connection.
If he really was just a tool as you say, why would she interact with him outside of the "bondage moments"? Why would she pretty herself and go on dates with him? Why would she say that she loves him? She could legit just call him after school and make him pleasure her and end there...yet that's not what happens.
As you say, she's kinda famous in school, even before she bonded with Sawada. She's the school madonna, everyone looks at her...and yet she chose Sawada and stays with him. It's been 55 chapters and it's all about them bonding more and more. When she got her ear pierced, her friend who saw only 1 earring directly went to Sawada to look for the other one....that should be reason enough that people that really care for Minezaki are ok with her interacting with him because she's happy.
I really don't understand this hate and this need to add another character so that she can be stolen from him. Because that's what you're making me understand: "realistically this, realistically that, realistically she will be stolen"...are you projecting by any chance?
And again with the "he knows her secret"...dude, she could have destroyed him socially in chapter 1, but she didn't. She felt he was a nice guy, that she could trust him and that he would accept her...and that's what happened and so they became "partners in crime"
Also, unattainable flower twisted blood is because she is the typical manga girl people only dare to look, but is also into really kinky stuff lol
EDIT We're also forgetting that Sawada did indeed grow as a character: he went from being unsure of interacting with Minezaki, to boldly calling himself her boyfriend. To me, that's growth.