I don't think my parents really suspect anything of my sexuality. Sure, they've asked me questions sometimes, and at my age, they sort of expect that their children are supposed to be seeing girls by now, but they know I am not the kind of guy who would really be carnally interested in girls anyway. I've got the fact that I tend to value relationships that are meaningful a lot more than those where the interests are purely lascivious to back up why I'm not coming home with a girl at my age. My parents know I am not interested in that, and at worst they might suspect I am asexual, which I am not, but it's not even half that bad of a guess.
If one day, I will happen to find a guy whom I can be honest with, whom I want to commit myself to romantically, then I will have no choice but to come out to my parents. Especially now that I am nearly 18, the age of majority, it would be madness to think that I am supposed to bend my values and live an inauthentic life just to please my parents and let them hold onto an image they have of me. A kind of version of myself that they create that is whom they love, instead of the bare personality I really am.
I've had my mother explicitly ask me whether I was gay just once, and it scared the hell out of me. It was totally unexpected, in public, and I broke out in sweat. I just told her that I didn't know, and I wasn't really interested in a relationship with anyone, and at the time, I really didn't know, and I really wasn't interested in a relationship with anyone. I can only really feel a romantic and sexual attraction to someone who takes me for who I am, and who will love me not in spite of all the asymmetry, and all of my brokenness and my problems, but because of it. Someone whom I can be able to talk to for hours and hours about everything under the sun. A real friend, put short, one of the 2 to 3 people a person on average can have whom they can be sincere with about everything. If it's just a relationship meant to fulfill some desires, a hollow shell, then it just would feel feigned to me.
And don't worry about your own logic sounding dumb, I really don't think it sounds dumb at all. You extract from your personal experience and you place it in the perfect context in your responses.