Why do some men treat pretty women like objects?

Heatherrr
A couple of times there has been random guys who treat me like a play piece on a board game. Down right disrespectful. For instance:
- I was standing in line getting food and some guy who always stares at me, but has never spoken to me, was standing in front of me. His friends walked over and stood in line behind me laughing and pushed me toward him while asking him if he had a hard on. And proceed to stand behind me as close as possible, so I couldn't move away.
- In the computer lab one time some guy was with his friend and switched seats just so he could look over my shoulder and spy on me. I was currently finishing a 30pg memoir for my Grandmother and it was really personal and heart wrenching and the two of them just kept on talking and judging it the whole time. And when I finished his friend goes "dude how was it?" and he just laughed and said "It was really corny, but sad dude."
- Another kid that always stares at me once walked by me and purposely bumped into me and I almost fell. So I turned around and said "what the hell" and he just smirked at me and kept walking.
- Some random guy started playing with my hair one time in line at starbucks, caught my bra and snapped it.
- One time I was walking and I guess my sunglasses fell out of my back pocket bc the dude behind me picked them up going "hey you dropped these" slide them in my pocket for me while simultaneously squeezing my ass.

I think one of my biggest problems is I don't know how to stand up for myself and when things like this happen, I just get so awkward and uncomfortable I stay quiet.
Why do some men treat pretty women like objects?
112 Opinion