Merely experiencing desire upon beholding someone is not to necessarily objectify. To wit:
I’ve been objectified by men when I’ve worn frumpy sweatshirts and baggy straight jeans: my butt was groped when I was arrayed that way at a hole-in-the-wall eatery. I’ve been objectified by men while I was wearing long, loose tunics and skirts topped by carefully-draped headscarves: I was asked if I was a “total freak under that thing”, the last word punctuated by an unmistakable gesture towards my scarf. Hell, I’ve been objectified by men for being a virgin who mostly stayed at home: a much-older man online told me that he found it titillating to think about me “locked away” and insinuated that if we got together, he’d rescue me to a liberated life of constant sex and nudity at his apartment.
Notice a pattern here?
Well, besides the fact that I wasn’t dressed or positioned in the way that people assume would attract a pervert, and the fact the these men were attracted to me. Their desire alone was hardly the issue.
Nor is the problem that they expressed desire. Expressing desire in a way that treats the person like a full human being (or at the very least allows for the desired person to gracefully extricate themselves from the situation) is not objectification.
The problem was that they made their attraction to me the sole focus of their interactions with me with a sense of entitlement that precluded my full humanity. None of them considered my consent and ensured that my ability to respond was hampered. Groper never said a word to me and took advantage of the fact that I wouldn’t want to make a scene and that he had plausible deniability in the form of his female partner, a woman far more conventionally attractive and attractively-dressed than me. Freak Boy used the fact that I was clearly a wide-eyed first-year with her nose buried in a book to catch me by surprise and throw me off my guard. Wannabe Liberator knew very well that I was as young and as insecure and as inexperienced as could be, so I didn’t know how to respond.
These are micro-level examples of objectification, where I, as a female person, was reduced to being a sexual object for the sexual gratification of a man. Nothing was considered about me other than my crotch-stiffening properties, least of all my willingness to participate in their expressed desires. I wasn’t a person, I was an object of fappery (or perhaps mockery, in the case of Freak Boy, though that’s irrelevant).
Taken to a macro level, objectification can become sexualization, where things are valued merely for their presumed ability to titillate rather than anything else about them. Bellydancing is one example. It certainly is sensual and can be incredibly sexy, but there is certainly more to it than the male gaze gives it credit for. It’s a way by which men and women express themselves, it’s an art form, and it has cultural history behind it.
Being turned on by something or someone is not objectification, it is sexual desire, something experienced by everyone but the asexual. Treating the thing or person in question as if they solely exist to turn you on is objectification. Taken to a societal level, where things are collectively considered to be worthwhile merely for their ability to turn people on (or inability thereof) is sexualization.